£'nt.

Wisconsin Geological and Natural History Survey.

E. A. BIKGE, Director.
BULLETIN NO. 2. SCIENTIFIC SERIES NO. 1.

/

INSTINCTS AND HABITS

SOLITARY WASPS

BY '„^c'^

George w. peckham

and'

Elizabeth G. Peckham.

MADISON, WIS.

PUBLISHED BY THE STATE

1898

^ • '/I

MAY 2 1 1984

TABLE OF CONTENTS.

CHAPTER I.

Page.

Ammophila and her Caterpillars .... 6

CHAPTER II.
The Great Golden Digger (Sphex ichneumonea) . . 33

CHAPTER in.

The Inhabitants op an Old Stump (Rhopalutn pecUcella-

tmn and Stigmus americanus) ..... 42

CHAPTER IV.
The Toilers op the Night {Crabro stirpicola) . . 46

CHAPTER V.

Two Spider Hunters [Salhcs conicus and Aporus fasci-

atus) ......... 53

CHAPTER VI.
An Island Settlement [Bembex spinolae) ... 58

CHAPTER VII.
The Little Flycatcher [Oxybelus quadrinotatus) . . 73

CHAPTER VIII.

The Wood-Borers [Trypoxylon albopilosum and Trypoxy-

lon rubrocincturn^ . . . . . . . 77

CHAPTER IX.
The Bug-Hunters (^Astata unicolor and Astata bicolor) . 88

iv CONTENTS.

CHAPTER X.

Page.

The Diodonti ........ 99

CHAPTER XI.
Some Grave Diggers [Cerceris and Pfiilanthus) . . 108

CHAPTER XII.
The Spider Ravishers {Pomjnlns and Agenia) . . 125

CHAPTER XIII.
The Enemies of the Orthoptera . . . .167

CHAPTER XIV.
The Mud- Daubers (Pelopaeus) . . . . .176

CHAPTER XV.

Extracts From Marchal's Monograph on Cerceris or-

NATA 200

CHAPTER XVI.
On the Sense of Direction in Wasps . . . .211

CHAPTER XVII.
The Stinging Habit in Wasps 220

CHAPTER XVIII.
Conclusions ..... . . 228

WISCONSIN GEOL.AND NAT. HIST. SURVEY.

BULLETIN II Pi

J- H Ernerron del.

SORIWttSTfRHUIKJCO.

PLATE I.

Fig. 1. Pompilus marginatus ? , X 2.

Fig. 2. Pompilus fuscipennis ? , X ^•

Fig. 3. Philanthus punctatus ? , X 2.

Fig. 4. Astata hicolo7- ? , X 2.

Fig. 5. Crabro stirjncola ? , X 2.

Fig. 6. Bembex spinolae ? , X 2.

Fig. 7. Pompilus quinquenotatus ? , X 2.

Fig. 8. Ceroeris clypeata ? , X 2.

WISCONSIN GEOL.AND NAT. HIST. SURVEY.

E3ULLETIN II PL. II

J. H. Emerron del.

HWrn«STERNllTHCl W

PLATE II.

Fig. 1. Harpactopus abdominaUs f , natural size.

Fig. 2. A')n')nophila urnaria ? , natural size.

Fig. 3, Chlorion coeruleum $ , natural size.

Fig. 4. Sphex iohneumonca 2 , natural size.

Fig. 5. Pelopaeus ceyyientarius ? , natural size.

PREFACE.

The work that has served as a basis for this volume has ex-
tended over several years, and has been done in Wisconsin, at
the residence of Dr. Charles A. Leuthstrom, to whose forbear-
ance in allowing iis to use his gardens as a hunting-ground, we
are greatly indebted. The field is a most favorable one since
:an island in the lake close by, acres of woodland all about, and
a farm with two vegetable gardens, one on the top of a hill and
one on lower ground, offer a rich variety of nesting places. It
is in the lower garden, which is bounded by woods, that the
wasps are found in greatest abundance.

The study of the solitary wasps was suggested to us by those
most interesting and delightful of all entomological papers,
the "Souvenirs Entomologiques" of J. H. Fabre, and however
widely our conclusions may differ, we have for M. Fabre and
for his work, the deepest respect and admiration.

We wish to express our indebtedness to Mr. W. H. Ashmead
of Washington, for his cordial interest in the work and for his
kindness in identifying for us the various species.

Milwaukee, October 30, 1897.

INSTINCTS AND HABITS OF THE SOLITARY

WASPS.

INTROBtrCTION.

Eor the purposes of tliis work wasps may be divided into two
classes, the social and the solitary. Of these, those of the latt^
class are much the more numerous, there being over one thou-
sand species in the United States alone, while there are only
about fifty species of the social genera. That the social kinds axe
better known is due to the fact that the great size to which
their communities often attain makes it comparatively easy to
study them.

The social wasps most commonly met with in Wisconsin are
the hornets and yellow-jackets of the genus Yespa, and a species
of Polistes that builds op^n combs. For the sake of comparison
let us sum up briefly the cycle of their lives. In the autumn
the queens, having mated with the drones, creep away into
crevices and sheltered comers where they pass the winter. In
the spring they may be seen seeking for suitable nesting places,
and forming, from the fibres of weather- beaten wood, which are
scraped off and chewed up, the first layer of ceils. So much
being accomplished the queen deposits her eggs, one in each cell,
and when these develop into grubs she feeds them until at the
end of a week or ten days they spin their cocoons and become
pupae. In from eight to ten days the perfect wasp is formed
and emerges from its cell ready to assume its share of responsi-
bility in the work of the nest. These first wasps are always
neuters, and hereafter all the duties which the queen has been
obliged to perfonn, with the single exception of egg-laying, fall

4 THE SOLITARY WASPS.

upon tliem. Before long many liimdreds of neuters are busj
at work, no drones appearing until the summer is somewhat
advanced. While the warm weather lasts the nest continues to
inciiease in size and numbers, but in the first cool days of fall
the neuters and queens desert it, leaving the helpless drones and
undeveloped grubs to starve. The neuters, after leading a
wandering life for two or thi-ee weeks, perish with the first
frosts, the queens alone being left, and doubtless many of these
also die in the severe cold winter.

The solitary wasps differ from the social, in having only two
sexes. Each female makes a separate nest and provisions it
by her own labor; and in many cases a new nest is made for
each egg. There is no cooperation among them, although in
certain genera, as Petopaeus and Bemhex, a number of individu-
als build close together, forming a colony. The nests may be
made of mud and attached, for shelter, under leaves, rocks, or
eaves of buildings, or may be burrows hollowed out in the
ground, in trees or in the stems of plants. The adult wasp lives
upon fruit or nectar but the yoimg grub or larva must have ani-
mal food, and here the parent wasp shows a rigid conservatism,
each species providing the sort of food that has been approved.
by its family for generations, one taking flies, another bugs, and
another beetles, caterpillars, grasshoppers, crickets, locusts, spi-
ders, cockroaches, aphides or other creatures, as the case may be.

The solitaiy wasps mate shortly after leaving the nest, in the
spring or summer. The males are irresponsible creatures, aiding
little, if at all, in the care of the family. When the egg-laying
time arrives the female secures her prey, which she either kills
or paralyzes, places it in the nest, lays the egg upon it, and then,
in most cases, closes the hole and takes no further interest in it,
going on to make new nests from day to day. In some genera
the female maintains a longer connection with her offspring,
not bringing all the provision at once but returning to feed the
larva as it grows, and only leaving the nest permanently when
the grub has spun its cocoon and become a pupa. %

The egg develops in from one to three days into a footless,

INTROD UCTION. 5

maggot-like creature wliicli feeds upon the store provided for it,
increasing rapidly in size, and entering tlie pupal stage in from
three days to two weeks. In the cocoon it passes through its
final metamorphosis, emerging as a perfect insect, perhaps in
two or three weeks, or, in many cases, after the winter months
have passed and summer has come again. Probably no solitary
wasp lives through the winter, those that come out in the spring
or summer perishing in the autumn.

The social hymenoptera are born into a community, and their
mental processes may be modified and assisted by education and
imitation, but the solitary wasp (with rare exceptions) comes
into the world absolutely alone. It has no knowledge of its
progenitors, which have perished long before, and no relations
with others of its kind. It must then depend entirely upon its
inherited instincts to determine the form of its activities, and
although these instincts are much more flexible than has been
generally supposed, and are often modified by individual judg-
ment and experience, they are still so complex and remarkable
as to offer a wide field for study and speculation.

THE SOLITARY WASPS.

CHAPTER I.

AMMOPHILA AND HER CATERPILLARS.

Plates II., fig. 2; III.; IV.; V.; VIIL, figs. 1-4.

Most graceful and attractive of all the wasps — "taille effil^e
tourmire svelte,'' as Fabre describes them, the Ammophiles, of
all the inhabitants of the garden, hold the first place in our af-
fections. Not so beautiful as the blue Pelopaens nor so indus-
trious as the little red-girdled Trypo.ryJon, their intelligence,
their distinct individuality, and their obliging tolerance of our
society make them an unfailing source of interest. They are,
moreover, the most remarkable of all genera in their stinging
habits, and few things have given us deeper pleasure than our
success in following the activities and penetrating the secrets of
their lives. In our neighborhood we have but two species of
Ammophila, urnaria Cresson (PL II., fig. 2), and gracilis Cres-
son, both of them being very slender bodied wasps of about an
inch in length, gracilis all black, and irrnaria with a red band
around the front end of the abdomen. With two exceptions
our observations relate to 'urnaria.

During the earlier part of the summer we had often seen
these wasps feeding upon the nectar of flowers, especially upon
that of the sorrel of which they are particularly fond, but at
that time we gave them but passing notice. One bright morn-
ing in the middle of July, however, we came upon one that was
so evidently hunting, and hunting in earnest, that we gave up
everything else to follow her. The ground was covered, more
or less thickly, with patches of purslane, and it was under these
weeds that our Ammophila was eagerly searching for her prey.
After thoroughly investigating one plant she would pass to
another, running three or four steps and then bounding ai

4f ,Z

AMMOPHILA AND HER CATERPILLARS. 7

though she were made of thistledown and were too light to re-
main upon the ground. We followed her easily, and as she was
in full view nearly all of the time we had ©very hope of wit-
nessing the capture, but in this we were destined to disappoint-
ment. We had been in attendance on her for about a quarter
of an hour when, after disappearing for a few moments under
the thick purslane leaves, she came out with a green caterpillar.
We had missed the wonderful sight of the paralyzer at work,
but we had no time to bemoan our loss for she was making off
at so rapid a pace that we were well occupied in keeping up with
her. She hurried along with the same motion as before, unem-
barrassed by the weight o"^ her victim. (Plate III.) Twice she
dropped it and circled over it a moment before taking it again.
For sixty feet she kept to open ground, passing between two rows
of bushes, but at the end of this division of the garden, she
plunged, very much to our dismay, into a field of standing com.
Here we had great difficulty in following her, since far from
keeping to her former orderly course, she zigzagged among the
plants in the most bewildering fashion, although keeping a gen-
eral direction of northeast. It seemed quite impossible that she
could know where she was going. The com rose to a height
of six feet all around us; the ground was uniform in appear-
ance,' and, to our eyes, each gi*oup of corn stalks was just like
every other group, and yet, without pause or hesitation, the
little creature passed quickly along, as we might through the
familiar streets of our native town.

At last she paused and laid her burden down. Ah ! the power
that has led her is not a blind, mechanically perfect instinct,
for she has traveled a little too far. She must go back one row
into the open space that she has already crossed, although not
just at this point. ISTothing like a nest is visible to us. The
surface of the ground looks all alike, and it is with exclamations
of wonder that we see our little guide lift two pellets of earth
which have served as a covering to a small opening running
down into the ground.

The way being thus prepared she hurries back with her wings

8 THE SOLITARY WASPS.

quivering and her whole manner betokening joyful triumph at
the completion of her task. We, in the meantime, have become
as much excited over the matter as she is herself. She picks
up the caterpillar, brings it to the mouth of the burrow and lays
it down. Then, backing in herself, she catches it in her mandi-
bles and drags it out of sight, leaving us full of admiration and
delight.

How clear and accurate must be the observing powers of these
wonderful little creatures! Every patch of ground must, for
them, have its own character; a pebble here, a larger stone
there, a trifling tuft of grass — these must be their landmarks.
And the wonder of it is that their interest in each nest is so
temporary. A burrow is dug, provisioned and closed up, all in
two or three days, and then another is made in a new place with
everything to learn over again.

From this time (July thirteenth) on to the first of September
our garden was full of these wasps, and they never lost their
fascination for us, although owing to a decided difl'erence be-
tween their taste and ours as to what constituted pleasant
weather all our knowledge of them was gained by the sweat of
our brows. When we wished to utilize the cool hours of the
morning or of the late afternoon in studying them, or thought
to take advantage of a cloud which cast a grateful shade over
the sun at noonday, where were our Ammophiles? Out of sight
entirely, or at best only to be seen idling about on the flowers
of the onion or sorrel. At such a time they seemed to have
no mission in life and no idea of duty. But when the air w.is
clear and bright and the mercury rose higher and higher, all
was changed. Their favorite working hours were from eleven
in the morning to three in the afternoon, and when they did
work they threw their whole souls into it. It was well that it
was so, for they certainly needed all the enthusiasm and perse-
verance that they could muster for such wearisome and disap-
pointing labor. Hour after hour was passed in search, and often
there was nothing to show at the end of it, for, since the cater-
pillars that they wanted were nocturnal species, most of them

AMMOPHILA AND HER CATERPILLARS. 9

were under ground in the day-time. The species observed hj
Fabre knew, by some subtle instinct, where to find the worm,,
and unearthed it from its burrow. Urnaria, on the contrary,
never dug for her prey, but hunted on bare ground, on the
purslane, and most of all on the bean-plants. These were ex-
amined carefully, the wasp going up and down the stems and
looking under every leaf, but the search was so frequently un-
successful that in estimating their w^ork we are inclined to think
that they can scarcely average one caterpillar a day. When
they were hunting over bare ground they often paused and'
seemed to listen, and in the beginning we expected to see them
burrow down and drag a victim from under the soil, but this
never happened.

In this species, as in every one that we have studied, we have
found a most interesting variation among the different individu-
als, not only in methods but in character and intellect. While
one was beg^^iled from her hunting by every sorrel blossom she
passed, another stuck to her work with indefatigable persever-
ance. While one stung her caterpillar so carelessly and made
her nest in so shiftless a way that her young could only survive
through some lucky chance, another devoted herself to these
duties not only with conscientious thoroughness but with an ap-
parent craving after artistic perfection that was touching to see.

The method employed by the AmmopJiilae in stinging their
prey is more complex than that of any other predatory wasp.
The larvas with which they provision their nests are made up
of thirteen segments and each of these has its own nervous
center or ganglion. Hence if the caterpillar is to be reduced to
a state of immobility, or to a state so nearly approaching im-
mobility that the egg may be safely laid upon it, a single sting,
such as is given by some of the Pompilidae to their captured
spiders, will be scarcely sufficient. All this we knew from Fa-
bre's "Souvenirs," and yet we were not at all prepared to believe
that any plain American wasp could supply us with such a
thrilling performance as that of the Gallic hirsuta, which he
so dramatically describes. We were, however, most anxious

10 THE SOLITARY WASPS.

to be present at the all-important moment that we might see for
ourselves just how and where AmmophUa urnaria stings her
\dctim,

For a whole week of scorching summer weather we lived in.
the bean patch, scorning fatigue. We quoted to each other the
example of Fabre's daughter Claire, whose determination to
-solve the problem of Odynerus led to a sun-stroke. We fol-
lowed scores of wasps as they hunted; we ran, we threw our-
selves upon the ground, we scrambled along on our hands and
knees in our desperate endeavors to keep them in view, and yet
they escaped us. After we had kept one in sight for an hour or
more some sudden flight would carry her far away and all our
labor was lost.

At last, however, our day came. We were doing a little
hunting on our own account, hoping to find some larvae which
we could drop in \'iew of the wasps and thus lead them to dis-
play their powers, when we saw an urnaria fly up from the
ground to the underside of a bean leaf and knock down a small
green caterpillar. Breathless with an excitement wliich will be
understood by those who have tasted the joy of such a moment,
we hung over the actors in our little drama. The ground was
bare, we were close by and could see every motion distinctly.
Nothing more }>erfect could have been desired.

The wasp attacked at once but was rudely repulsed, the cater-
pillar rolling and unrolling itself rapidly and with the most
violent contortions of the whole body. Again and again its ad-
versary descended but failed to gain a hold. The caterpillar
in its struggles, flung itself here and there over the ground, and
had there been any grass or other covering near by it might have
reached a place of partial safety, but there was no shelter within
reach, and at the fifth attack the wasp succeeded in alighting
over it, near the anterior end, and in grasping its body firmly
in her mandibles. Standing high on her long legs and disre-
garding the continued struggles of her victim she lifted it from
the ground, curved the end of her abdomen under its body,
•and darted her sting between the third and fourth segments.

AMMOPHILA AND HER CATERPILLARS. 11

JFrom this instant there was a complete cessation of movement
on the part of the unfortunate caterpillar. Limp and helpless,
it could offer no further opposition to the will of its conqueror.
Por some moments the wasp remained motionless, and then,
withdrawing her sting, she plunged it successively between the
third and the second, and between the second and the first seg-
ments. (Plate lY.)

The caterpillar was now left lying on the ground. For a
moment the wasp circled above it and then, descending, seized
it again, further back this time, and with great deliberation and
nicety of action gave it four more stings, beginning between the
ninth and tenth segments and progressing backward.

Urnaria, probably feeling — as we certainly did — a reaction,
from the strain of the last few minutes, and a relief at the com-
pletion of her task, now rested from her labors. Standing on
the ground close by she proceeded to smooth her body with heir
long hind legs, standing in the meantime, almost on her head,
with her abdomen direct-ed upward. She then gave her face
a thorough washing and rubbing with her first legs, and not
until she had made a complete and satisfactory toilet did she re-
turn to the caterpillar.

We saw Amniophihi capture her prey only three times during
the whole summer, but from these observations and from the
condition of her caterpillars taken at various times from nests,
her method seems to be wonderfully close to that of hirmita,
with just about the same amount of variation in different indi-
viduals.

Thus in our second example, she stung the first three seg-
ments in the regular order, the third, the second, and lastly (and
most persistently) the first. She then went on, without a pause,
to sting the fourth, fifth, sixth, and seventh, stopping at this
point and leaving the posterior segments untouched. In our
first example, it will be remembered, the middle segments were
spared. The stinging being completed, she proceeded to the
process known as malaxation, which consists in repeatedly
squeezing the neck of the caterpillar, or other victim, between

12 THE SOLITARY WASPS.

the mandibles, the subject of the treatment being turned around
and around so that all sides may be equally affected.

In our third case a caterpillar which we had caught was
placed in front of a wasp just after she had carried the second
larva into her nest. She seemed rather indifferent to it, pass-
ing it once or twice as she ran about, but finally picked it up
Rnd gave it one prolonged sting between the third and fourth
segments. She then spent a long time in squeezing the neck^
pinching it again and again. It w^as then left on the ground,
and as she showed no further interest in it we carried it home
for further study.

In the three captures, then, that came under our observation^
all the caterpillare being of the same species and almost exactly
of the same size, three different methods were employed. In
the first, seven stings were given at the extremities, the middle
segments being left untouched, and no malaxation was prac-
ticed. In the second, seven stings again but given in the an-
terior and middle segments, followed by slight malaxation. In
the third, only one sting was given but the malaxation was pro-
longed and severe.

Let us now compare these variations with those of Fabre. In
his first case the sting entered at twelve different points, be-
ginning between the first and second segments and progressing
regularly backward. There was no malaxation. In his sec-
ond example the third, second and first segments were stung in
the order given, and thereafter each succeeding segment up to
the ninth, nine stings being given in all, with careful malaxation
following. In his later experiments, which seeim to have been
numerous, he found that as a usual thing all the segments were
stung, although the posterior three or four were occasionally
spared, but that the order in which they were operated upon, aa
well as the amount of malaxation, was very variable.*

*M. Fabre was most fortunate in making Mrsuta sting under artifi-
cial conditions. Our experience with urnaria, on the contrary, recalls
his failures with sahiilosa. No matter how carefully we arrang-ed for
an experiment, placing the glass over the wasp out of doors, with the

AMMOPHILA AND HER CATERPILLARS. 13

Our conclusions, then, as to Ammophila's methods of sting-
ing agree fairly well with those of Fabre. There is, however,
one important exception. In his cases the middle segments,
upon one of which the egg is laid in our species as well as in his,
were invariably stung, and this he considers a point of extreme
importance. In one of cur cases the middle segments were not
touched.

The point in which our observations differ most widely from
those of Fabre is in the condition of the caterpillars after the
stinging. He seems to have found that they always lived a long
time but in a motionless or nearly motionless state, and he
d^vells at length upon the necessity of both of these conditions
since he believes that while the wasp larva must have perfectly
fresh food, any violent motion would imperil its safety. As a
matter of fact we found a wide variation in the thoroughness
with which the wasps performed their task. We had, in all,
fifteen caterpillars upon which urnaria had worked her will,
and while a few of them fulfilled to a nicety the conditions which
Fabre believes to be imperative, most of them were far from
doing so. Some of them lived only three days, others a little
longer, while still others showed signs of life at the end of two
weeks. Uruaiia stores two caterpillars and in more than one
instance the second one died and became discolored before the
fii"st one was entirely eaten. The wasp larva did not, as might
have been expected, find fault with this arrangement, but pro-
"ceeded to attack number two with good appetite, ate it all up, and
then spun its cocoon as though nothing' unpleasant had occurred.

The second condition was also violated. In one case the bite
of the newly hatched larva caused the caterpillar to rear upon
-end in so violent a manner that it looked as though the little
creature would surely be dislodged. Another caterpillar kept
up a continuous wriggling without any external stimulation and

sun at its hottest, while she was in the full fervor of hunting, and of-
fering her the caterpillars that she preferred above all others, the fact
of imprisonment was the only one present to her consciousness, and
she never ceased in her restless endeavors to escape.

14 THE SOLITARY WASPS.

when it was touched it rolled about almost £s these larvae do in
a healthy state, and yet the egg was not shaken off. The cater-
pillar which received but a single sting, although not motionless,
would have been a safer repository for the egg than either of
these. Others fulfilled Fabre's condition perfectly, lying im-
movable except when stimulated and then responding only by a
slight quivering of the legs or skin.

To show more exactly the amount of variation we quote
from our notes on the subject. These notes were mad© from
day to day.

No. 15. July 13. Took two caterpillars from nest just after the sec-
ond one had been put in. Both move posterior end of body without
stimulation.

July 14, A. M. Caterpillars both alive. The egg- has hatched and
the one to which the larva is attached wriggles violently and con-
stantly rears up at anterior end. P. M. Wasp larva eating. Caterpil-
lar naoves but little. The second caterpillar is still lively, moving at
posterior end.

July 15. Wasp larva has grown large and green. The caterpillar does
not move and the posterior half has turned yellow. The second cater-
pillar moves only when stimulated and then only at the posterior end.

July 17, 7:20 P. M. The second caterpillar is alive and moves when
stimulated.

Julj'^ 18, 9 A. M. The second caterpillar is dead. The antei-ior two-
thirds of the venter are green but the resit of the body has turned
brown. It lived four days and a half after being stung. The wasp
larva is still at work on the first caterpillar. — 6:30 P. M. The wasp
larva has just begun to eat the second caterpillar.

July 19, 10 A. M. The wasp larva has eaten nearly all of the second
caterpillar since last night. Have placed earth in bottom of tube to
see whether it will spin its cocoon.

July 21, 9 A. M. Lai*va has just spun cocoon. It ate half of the in-
side of the second caterpillar, evidently without regard to the vital
organs, taking everything as it came. The length of the cocoon is
14 mm., and the greatest width 6 mm. Color, light yellow.

No. 22. July 23, 9 A. M. Took from the nest the caterpillar which
we saw stung yesterday.* It was much quieter than those in the nest

*This caterpillar had been stung in seven places, at the anterior and
posterior ends. Owing to some disturbing element the egg, instead
of being laid upon it, was dropped on the ground.

AMMOPHILA AND HER CATERPILLARS. 15

of No. 15. It does not move spontaneously biat when it is touched the
legs, particularly the anterior ones, quiver like those of a spider that
has been stung.

July 24. When touched, moves at anterior end.

July 25, 9 A. M. The caterpillar is dead and some of the segments
have turned yellow.

No. 25. July 25, P. il. Took three caterpillars. Two of these were
from a nest. Of these the first had the e.gg (6 mm. long) attached on
the right side of the sixth segment. The second one, we saw stung"
this morning. Seven stings were given in the first seven segments,
with some malaxation. The third caterpillar is one which we offered
to the wasp and which received one sting, in the third segment, fol-
lowed by severe malaxation. All three are quiet but move w^hen
stimulated.

July 26, 9 A. M. Egg not yet hatched. The third caterpillar is alive.
The posterior end, beyond fifth segment, moves w^ithout stimulation,,
stretching out and upward. The posterior legs cling to the finger
tightly enough to support the weight of its body when it is lifted. The
paralysis is general but is much lighter toward the posterior end.

July 27, 7:30 A. M. The third caterpillar is still lively but is not so
plump. The posterior legs cling to the finger and support the body,
the anterior end hanging down. These legs also make efforts to walk.
So far as the egg is concerned this caterpillar would serve as well as
those found in the nest. It has passed fseces twice.

July 27, 8 A. M. The egg lias hatched and chlorophyll is visible in
the larva.

July 28, 8 A. M. Larva growing fast. It is all green in color except
the mouth, resembling the caterpillar thait it is eating. This cater-
pillar is dead as is also the second one, which has begun to turn yel-
low at the anal segments. The third caterpillar is much shrunken but.
is still alive, at least in the posterior half.

July 30, 8 A. M. The larva has begun to eat the second caterpillar.
The third caterpillar is dead.

August 1, 9:30 A. M. The lar\'a has spun its cocoon which is 15 mm-
long, and light yellow in color.

No. 56. August 17. We saw an AmmophUa taking a caterpillar into-
her nest at eleven in the morning. At five in the afternoon we took it
out. The egg was placed on one side of the sixth segment, near the
dorsum. The caterpillar is very imperfectly paralyzed, all its posterior
segments and the posterior feet wriggling violently when it is touched.
This is the most active caterpillar that we have seen so far, and the
egg must be tightly fastened on or it would be lost. The wasp appears
to have stung only as far back as the fifth or sixth segment, the sec-

16 THE SOLITARY WASPS.

ond part of the process being omitted. Touching it in front causes
the posterior legs to open and close, while the posterior half of the
body is thrown violently to one side.

August 18, 9 A. M. The caterpillar jerks up its posterior half with-
out being touched. When stimulated it is so violent that we are con-
cerned lest the egg be dislodged.

August 18, 10 A. M. We have just secured the caterpillar which
should have complet-ed the provisioning of this nest, the wasp having
deserted it on finding that her burrow had been disturbed. This one
Jias been stung in all the segments since it cannot move the posterior
Jialf about, nor wriggle as the first one does. Its neck, however, has
not been malaxed, as the mouth parts open and shut when touched,
and hold anj thing that is placed in them. The first caterpillar stung
by the wasp had been so malaxed that the mouth parts were paralyzed.

August 19. The first caterpillar is still lively, vv^hile the second
shows but little movement. We put both, with the egg, into alcohol.

No. 79. August 31. At eleven o'clock this morning we saw an
urnaria storing a short, fat, brown caterpillar. At five in the afternoon
we opened the nest and found not only the one that we had seen taken
in but also a longer, thinner, green one. Upon this one was a w^asp
larva about one day old, which shows that, in all probability, three
•days must have elapsed between the storing of the first and second
caterpillars. Besides the wasp larva, which has been attacked by
something and looks sickly, there are, upon the unfortunate green
caterpillar, three small parasitic larvae which all look plump and
iealthy. In spite of being obliged to furnish food to all these creatures
the caterpillar is still alive although a good deal shrunken and the
worse for wear. The one put into the nest today is alive but only
moves when stimulated.

September 1. Both caterpillars are alive. The wasp larva is dead,
but the parasites are still feeding on the green one and are doing
well.

September 2. Both caterpillars are alive. The green one is turning
yellow at the eighth segment. It is on this segment that the three
parasites are fixed, on the venter between the fourth and fifth pairs of
feet. They are growing fast. The brown caterpillar has also a larva
of some kind, which hatched today. It is placed on the right side be-
tween the fourth and fifth rings, just behind the third pair of feet.

September 3, 9 A. M. The green caterpillar is dead and has turned
black. Only one parasite is to be seen and that one is boring into the
body of its host. The brown caterpillar is still alive. Its parasite is
large and is eating fast.

September 4. The parasite inside the green caterpillar is still eat>-

AMMOPHILA AND HER CATEEPILLARS. 17

ing. That on the brown one is crawling about on the outside. This
brown caterpillar is barely alive.

September 5. The larva in the green caterpillar is eating as before.
The brown caterpillar is dead and the parasite has gone inside of its
body.

September 6. The first larva has burrowed into the earth, having
eaten all the inside out of its prey. The other one is eating as before.

September 7. The brown caterpillar's parasite has also burrowed
into tJie ground.

No. 80. Septembex 1. Just after noon yesterday we saw an uncom-
monly large urnaria carry an uncommonly large green caterpillar into
her nest. At eleven o'clock this morning we took it out. The egg is
on the left side of the seventh segment.

September 3, 11 A. M. The egg has just I'atched. It is nearly three
days since it w^as laid. The w^eather is cool and it may be for that rea-
son that a longer time than usual has elapsed.

September 4. The larva is growing slowly.

September 5. The larva grows very slowly. The caterpillar is alive
and green.

September 6. The caterpillar is alive and looks fresh. The larva
eats and grows very slowly.

September 8. The caterpillar is still alive and green. The larva has
increased a very little in size.

September 10, 5 P. M The larva has grown very fast since yester-
day morning. The caterpillar is dead. The last four segments have
tiimed brown, but the rest is of the original green color.

September 15. The larva is still eating the dark colored remains of
the caterpillar. It is now very large and fat and has taken on the
green color of the caterpillar which it has devoured.

September 16. The larva is spinning its cocoon.

No. 81. August 31. This afternoon we saw an A. gracilis carry a
green caterpillar, larger than the one ordinarily taken by urnaria, but
not so large as that of No. 80, a long distance (261 ft.) over all sorts of
ground. It received very rough usage and when, the wasp having de-
serted it, we took it into our possession, it was so contorted that the
head and the first four segments were not in a plane yvith the rest of
the body. The third segment, which had been grasped by the mandi-
bles of the wasp, was badly bruised and discolored.

September 1. The caterpillar, as we look at it through the glass
slide which covers the box in which it lies, continually moves the
mouth parts and the anterior segments of its body. Now and then it
slowly lifts the posterior half of its body and then lets it go back.

2

18 THE SOLITARY WASPS.

This is wifrh-out the slig-htest stimulation as we do not even touch the
box nor the shelf upon which it stands. The movement is not at all
violent as in other caterpillars (see Nos. 15 and 56). The muscles have
relaxed a little so as to let down the anterior segments, but the body is
still in a curled up position.

September 5. The caterpillar is alive and is still tightly curled up.

September 6. It now lies flat. The body is shrunken and the colo-r
lias faded to a li\-id blue.

September 15. The caterpillar looks as if it were dead but still re-
isponds to careful stimulation.

September 23. The caterpillar is now of a sickly yellowish hue and
is shrunken to a quarter of its original size. We get a scarcely per-
ceptible response to stimulation.

September 25. The caterpillar is unquestionably dead.

Among tlie fifteen caterpillars that we have taken from the
nests of nrnaria three kinds are represented, twelve of them
belonging to one species, two to the second, and one to the third.

The egg, which is laid upon the side of the sixth or seventh
segment* (PL VIII., fig. 5), hatches in from two to three days;
the larva spends from six davs to two weeks in eating, and then
spins its pale yellowish cocoon.

The nesting habits of urnaria closely resemble those of the
other members of the genus, as reported by various observers.
The spot chosen is in firm soil, sometimes in open ground but
much more freqeuntly under the leaves of some plant. The
plan is a very simple one. A tunnel of about an inch in length
leads to the pocket in which the caterpillars are stored. There is
no hardening of the walls in any part. We took pains to draw
every nest that we opened, and, as will be seen from the illus-
trations of some of them, there was a very considerable variation
in the minor details, such as the obliquity of the entrance tun-
nel, the shape of the pocket, and the angle at which the tunnel
and pocket were joined. . (PL VIIL, figs. 1-4.)

The work is done with the mandibles and the first legs.
When it has proceeded so far that the wasp is partly hidden, she

*In the drawing the egg is, by mistake, shown upon the eighth seg-
ment.

AMMOPHILA AND HER CATERPILLARS. 19

begins to carry the eartli to a little distance from the nest. In
■doing this she backs up to the edge of the opening and flying a
little way, gives a sort of flirt which throws the pellet that she
carries in her mandibles to a distance. She then alights where
she is and pauses a moment before she runs back to the hole, or,
in some cases, darts back on the wing. We watched the process
of nest-making five times during the summer. In the first in-
stance Ammophila, having made her excavation, ran off to a
distance and after some search returned with a good sized lump
■of earth. This she laid over the opening which was now entirely
hidden. She then flew to the bean patch close by, but after ten
minutes she came back and looked at her nest. It was so neatly
covered as to be almost indistinguishable, but to this fastidious
little creature something seemed lacking. She pulled away the
cover, carried out three or four more loads, and then began to
search for another piece for closing. After a time she came
liurrying back with a lump of earth, but when close to the nest
she concluded that it would not do, dropped it, and ran off in
another direction. Presently she found one which fitted into the
hole exactly, and after placing it she brought a much smaller
piece which she put above and to one side. She then stood
back and surveyed the whole and it seemed to us that we could
read pride and satisfaction in her mien. She then flew away
and we supposed that that stage of the work was certainly com-
pleted. Upon coming back two hours later, however, we found
that she had been trying some more improvements, as a number
of little pellets had been piled up over the nest. This wasp, by
the way, never succeeded in finding a caterpillar, since when we
opened the nest a few days later it was still empty. Perhaps
she came to some untimely end.

Of the other wasps that we saw making a temporary closure
of their nests, one wedgied a good sized stone deep down into
the neck of the burrow and then filled the space above, eolidly,
with smaller stones and earth. Another placed two lumps of
earth just below the surface of the ground, filled the opening
with pellets loosely thrown in, and then kicked some light dust

20 THE SOLITARY WASPS.

over tlie whole. The others used only two or three lumps of
earth which they fitted neatly into the opening just below the
surface. Although it is usual for urnaria to leave her nest
closed w^hile she is off searching for her prey, there is no invaria-
ble rule in the matter even for single individuals. Once hav-
ing seen a wasp dig her nest and close it up, we drew some radi-
ating lines from the spot, in the light dust that covered the
place, that we might find it again. When we returned, two
hours later, the same wasp had made a nest four or five inches
distant from the first one, and had left it wide open, while she
had gone off to search for her caterpillar. She had probably"
been alarmed by the marks that we had made and had felt it
necessary to dig a new nest, but being in a hurry to lay her egg
had omitted the usual process of closing it. We witnessed the
storing of the caterpillar and the final closing.

From Fabre we learn that A. argentata and A. sahulo-
sa, like our own itrnaria, close the nest as soon as it has been,
made, at least when the provisioning is to be postponed until
the next day, while A. liolosericea leaves it open until it is com-
pletely stored. He suggests an explanation for this variation
by dwelling upon the inconvenience that would result if it were
opened every time that the wasp brought in a caterpillar, since
liolosericea stores up five or six small larvae instead of one or
two large ones. But what, then, shall be said of A. yarrowi,
which, a.ccording to Dr. Williston, while it also stores a number
of small caterpillars, takes the greatest pains to close and con-
ceal the entrance every time that it comes out? We see the
same habit in other genera where the mother continually passes
in and out, as in Bemhex and Oxyhelus.

Fabre thinks that A. Mrsuta has the habit, unusual for Am-
mophila, of catching her prey first and then digging the hole in
which she bestows it. As she takes only one large caterpillar
she is thus relieved of the necessity of closing the nest more
than once.

As has been said, urnaria usually hunts a long time before
she finds her caterpillar, and one or two days may pass before-

AMMOPHILA AND HER CATERPILLARS. 21

anytking is put into the nest. During this prolonged search
she often revisits the spot and thus keeps fresh the memory of
its locality. As soon as the first caterpillar is stored she lays an
e^g on it and then closes the nest as before. The second one
may be brought in within a few hours, but in one instance that
came under our notice (No. 79), we feel sure that the interval
was as much as three days. We saw the interment of the second
caterpillar, and upon excavating, found upon the first one a
larva at least a day old; and we suppose that at least two days
had elapsed between the laying and the hatching of the egg.

When the provisioning is completed the time arrives for the
final closing of the nest, and in this, as in all the processes of
Ammophila, the character of the work differs with the individ-
ual. For example, of two wasps that we saw close their nests
on the same day, one wedged two or three pellets into the top
of the hole, kicked in a little dust and then smoothed the sur-
face over, finishing it all within five minutes. This one seemed
possessed by a spirit of hurry and bustle, and did not believe in
spending time on non-essentials. The other, on the contrary,
was an artist, an idealist. She worked for an hour, first filling
the neck of the burrow with fine earth which was jammed down
with much energy, this part of the work being accompanied by
a loud and cheerful humming, and next arranging the surface
of the ground with scrupulous care, and sweeping every par-
ticle of dust to a distance. Even then she was not satisfied
but went scampering around hunting for some fitting object to
crown the whole. First she tried to drag a withered leaf to the
spot but the long stem stuck in the ground and embarrassed her.
Relinquishing this she ran along a branch of the plant under
which she was working and, leaning over, picked up from the
ground below a good sized stone, but the effort was too much
for her and she turned a somersault on to the ground. She
then started to bring a large lump of earth but this evidently
did not come up to her ideal for she dropped it after a moment,
and seizing another dry leaf carried it successfully to the spot
and placed it directly over the nest. A third instance of the

22 THE SOLITARY WASPS.

final closing of the nest was intermediate between these two, the
work occupying twenty minutes. The wasp first put a plug
well down, then dropped in several large pellets and brushed
in a quantity of fine earth, and finally smoothed the surface
over.

We had another much less worthy example, one, indeed, that
went to the extreme of carelessness. We first saw her in the
morning carrying her caterpillar across the field. She frequently
dropped it and ran or flew to a little distance, and when she
took it again the venter was sometimes up and sometimes down,
just as it happened. Her nest was a very poor affair just be-
neath the surface, and after the caterpillar was carried in, it
was visible from above. She filled the hole with loose particles
of earth and then scratched the surface of the ground a little in
a perfunctory sort of way, as different as possible from the pains-
taking labor 'that we had been accustomed to in her sisters.
That afternoon we opened the nest and removed its contents.
The next morning we saw this wasp bringing home her second
caterpillar. She was much puzzled and disturbed at the de-
struction of her nest, and hunted for it for an hour and a half,
leaving the caterpillar on the ground near by. We could not
help feeling sorry that we had interrupted the contented rou-
tine of her life. She finally gave up in despair and we took
possession of the deserted caterpillar.

Just here must be told the story of one little wasp whose in-
dividuality stands out in our minds more distinctly than that
of any of the others. Wei remember her as the most fastidious
and perfect little worker of the whole season, so nice was she
in her adaptation of means to ends, so busy and contented in her
labor of love, and so pretty in her pride over her completed
work. In filling up her neet she put her head down into it and
bit away the loose earth from the sides, letting it fall to the bot-
tom of the burrow, and then, after a quantity had accumulated,
jammed it down with her head. Earth was then brought from
the outside and pressed in, and then more was bitten from the
sides. When, at last, the filling was level with the ground, she

AMMOPHILA AND HER CATERPILLABS. 23

"brought a quantity of fine grains of dirt to the spot and pick-
ing up a small pebble in her mandibles, used it as a hammer
in pounding th^em down with rapid strokes, thus making this
spot as hard and firm as the surrounding surface. (Plate Y.)
Before we could recover from our astonishment at this perfor-
mance she had dropped her stone and was bringing more earth.
"We then threw ourselves down on the ground that not a motion
might be lost, and in a moment we saw her pick up the pebble
and again pound the earth into place with it, hammering now
here and now there until all was level. Once more the whole
process was repeated, and then the little creature, all unconscious
of the commotion that she had aroused in our minds, uncon-
scious, indeed, of our very existence and intent only on doing
her work and doing it well, gave one final, comprehensive
glance around and flew away.

We are claiming a great deal for Ammophila when we say
that she improvised a tool and made intelligent use of it, for
such actions are rare even among the higher mammals, but for-
tunately our observation does not stand alone, although we sup-
posed this to be the case at the time that it was made. Some
weeks later, seeing a note of a similar occurrence by Dr. S. W.
Williston, of Kansas University, we wrote to him on the sub-
ject. In his reply he said that he had waited for a year before
venturing to publish his observation, fearing that so remarkable
a statement would not be credited. His account* is so interest-
ing that we quote it at length.

NOTE ON THE HABITS OF AMMOPHILA.
By S. W. Williston, Lawrence, Kan.
Even the casual observer, to whom all insects are bug-s, cannot help
but be struck by the great diversity and number of the fossorial Hy-
menoptera of the plains. Water is often inaccessible, trees there are few
or none, and only in places is the veg-etation at all abundant. A much
larger proportion of insects, hence, lind it necessary to live or breed
in holes in the ground, than is the case in more favored localities. Es-
pecially is this the ease with tihe Hymenoptera, great numbers and

*EntomologicQl News, Vol. III., 1892, p. 85.

24 THE SOLITARY WASPS.

many species of which thus breed in excavations made by them-
selves.

While packing specimens on an open space, uncovered by buffalo
grass, in the extreme western part of Kansas, the early part of last
July, the attention of a friend and myself was attracted by the numer-
ous wasps that were constantly alighting upon the ground. The hard,
smooth, baked surface showed no indications of disturbance, and it
was not till we had attentively watched the insects that we learned what
they were doing. The wasp is a very slender one, more than an inch
in length, with a slender, pedicellate abdomen; it is known to ento-
m.ologists as Animophila Yarrowi Cres. They were so numerous that
one was distracted by their very multiplicity, but, by singling out dif-
ferent individuals, we were enabled to verify each detail of their opera-
tions. An insect, alighting, ran about on the smooth, hard surface till
it had found a suitable spot to begin its excavation, which was made
about a quarter of an inch in diameter, nearly vertical, and carried to
a depth of about four inches, as was shown by opening a number of
them. The earth, as removed, was formed into a rounded pellet and
carefully carried to the neighboring grass and dropped. For the first
half of an inch or so the hole was made of a slightly greater diameter.
When the excavation had be«n carried to the required depth, the wasp,
after a survey of the premises, flying away, soon returned with a large
pebble in its mandibles, which it carefully deposited within the open-
ing; then, standing over the entrance upon her four posterior feet, she
(I say she, for it was evident that they were all females) rapidly and
most amusingly scraped the dust with her two front feet, "hand over
hand," back beneath her, till she had filled the hole above the stone to
the top. The operation so far was remarkable enough, but the next
procedure was more so. When she had heaped up the dirt to her satis-
faction, she again flew away and immediately returned with a
smaller pebble, perhaps an eighth of an inch in diameter, and then
standing more nearly erect, with the front feet folded beneath her, she
pressed down the dust all over and about the opening, smoothing off
the surface, and accompanying the action -with, a peculiar rasping
sound. After all this was done, and she spent several minutes each
time in thus stamping the earth so that only a keen eye could detect
any abrasion of the surface, she laid aside the little pebble and fl.ew
aw^ay to be gone some minutes. Soon, however, she comes back with
a heavy flight, scarcely able to sustain the soft green larva, as long as
herself, that she brings. The larva is laid upon the ground, a little to
one side, when, going to the spot where she had industriously labored,
by a few, rapid strokes she throws out the dust and withdraws the
stone cover, laying it aside. Next, the larva is dragged down the hole,

AMMOPHILA AND HER CATERPILLARS. 25

-where the wasp remains for a few minutes, afterwards returning and
closing- up the entrance precisely as before. This, we thought, was
the end, and supposed that the wasp would now be off about her other
affairs, but not so; soon she returns with another larva, precisely like
the first, and the whole operation is again repeated. And not only the
second time, but again and again, till four or five of the larvae have
been stored up for the sustainment of her future offspring. Once,
while a wasp had gone down the hole with a larva, my friend quietly
removed the door stone that she had placed by the entrance. Keturn-
ing, she looked about for her door, but not finding it, apparently mis-
trusted the honesty of a neighbor, which had just descended, leaving
her own door temptingly near. She purloined this pebble and was
making off with it, when the rightful owner appeared and gave chase,
•compelling her to relinquish it.

The things that struck us as most remarkable were the unerring
judgment in the selection of a pebble of precisely the right size to fit
the entrance, and the use of the small pebble in smoothing down and
packing the soil over the opening, together with the instinct that
taught them to remove everj.' evidence that the earth had been dis-
turbed.

Since the wasps of our two species of Ammophila make their
nests first and then do their hunting it follows that they must
sometimes carry their prey for a considerable distance. The
most ambitious attempt of this kind that we ever witnessed is the
subject of one of our observations on the habits of A. gracilis.

The wasp was first seen carrying a large green caterpillar,
which projected at both ends beyond her own body, across the
potato field at the lower end of the garden. We could not tell
how far she had already brought it, but judging by the direction
from which she was coming, and by the fact that we had never
«een that species of caterpillar in the garden, she had probably
come through the fence from the woods beyond. She moved
along briskly over the remaining part of the potato field, and
then through an adjoining bean patch into the com field. This
had been a place of much anxiety to us earlier in the summer
but now the corn had been stacked and we could follow her
without difficulty. So far she had been going due south, but
now she made a turn and plunged into the long, tangled grass
which grew around and among some large, overgrown raspberry

26 THE SOLITARY WASPS.

bushes. To keep track of lier here seemed a hopeless task, but
we resolved to do our best and followed anxiously after. The
wasp worked her way along about two inches above the ground
and very much below the top of the grass, clinging to the blades
with her feet and making surprisingly good progress. When
half way through the raspberry bushes she carried the cater-
pillar up on to a branch, deposited it there, and after circling
about to take her bearings, flew away, doubtless to visit her nest
and to make sure that she was going in the right direction.

We, ourselves, were very glad of the chance to rest our tired
eyes and nerves from the strain of following her. The journey,,
so far, had occupied nearly an hour, at almost every instant of
wliicli it had been exceedingly difficult to keep her in view-
But for our united efforts we should certainly have failed.

While standing guard over the caterpillar we noticed that it
moved its head from side to side, showing that the first segment
could not have been severely stung as is usually the case in the
work of urnaria.

In five minutes the wasp returned and, with the air of feeling
that everything was right, picked up her burden and carried it
laboriously through the remaining bushes and then through the
grassy space that edged the garden, as far as the rail fence which
separated this part of the grounds from the woods. Without a
pause she climbed on to this fence to the height of the second
rail, passed through, and flew down on the further side. Here
she paused a moment, perhaps to take breath, and we looked at
each other in some dismay. Whither was she leading us? We
had now been following her for over an hour and she looked
equal to as much again as she started eff once more, rapidly this
time, for the grass was short here and the traveling was easy.
Soon, however, it became evident that things were going wrong,
although we could not determine what was the matter. The
caterpillar was laid down while the wasp absented herself for six
minutes. She returned and carried it for fifteen minutes and
then left it for half an hour. Once more she came back, and
carried it for ten minutes, and then she flew away. It was now

AMMOPHILA AND HER CATERPILLARS. 27

four o'clock, and we had been following her since two. "We
watched over the caterpillar for an hour longer, but saw no more
of the wasp.

Did she become discouraged at the magnitude of her task?
It would have been a thousand times easier for her to have dug
her nest close by the place of capture, but perhaps she had one
larva already stored with her egg upon it. The caterpillar was
carried two hundred and sixty-one feet while we watched her,
with an unknown distanc-e at each end to complete the line be-
tween the place of capture and the nest. She could scarcely
have lost her way since at every return she proceeded on her
journey in one general direction without any hesitation. It
seems probable then, that she had hunted too far afield and did
not realize, when she started with her booty, what an undertak-
ing it would be to carry it to her nest.

The affairs of Ammophila must frequently go wrong, since in
still another of our few examples we saw much trouble and labor
wasted. The wasp, in this case an nrnaria, captured her cater-
pillar successfully and proceeded to carry it off. She was fax
from being in a hurry, going along for a foot or so and then
making a long pause, during which she would lay it down and
either circle above it, perhaps to take bearings, or spend the
time in cleaning herself off, stroking and smoothing every part
of her body with the utmost care and deliberation. Her stops
were so frequent and so lengthy that nearly an hour was occu-
pied in going about twenty-five feet. When, at last, the nest
was reached, the plug was removed from the entrance and the
caterpillar dragged in, but almost immediately the wasp came
out backwards with the point of an egg projecting from the ex-
tremity of her abdomen. She ran around and around the nest
in a distracted way four or five times and then went back^
dragged the caterpillar out, and carried it away. The egg came
out further and further, and finally dropped on the ground and
was lost. The wasp, carrying the caterpillar, led us a long
dance, in a great semicircle over the field, coming back to the
nest at last. Instead of going in, however, she was about to

28 THE SOLITARY WASPS.

start off on another tour when we took her prey from her and
placed it in the nest. The wasp remained in the neighborhood
for over an hour, but finally disappeared. The nest was not
closed, and when we dug it up on the following day it contained
only the caterpillar that we had put in.

Our second example of gracilis promised well in the begin-
ning but turned out badly. She was a big, powerful creature
and, when we saw her first, was carrying large pellets of earth,
in her mandibles, out of her tunnel and flinging them away.
This was at two o'clock in the afternoon and within half an hour
she had finished the nest and had filled in the upper part of it,
but in a very untidy fashion, throwing in some bits of cornstalk
and pellets of earth and then scratching in a little dust.

On the next day, September fourth, the wasp came back at
about ten o'clock and spent a few minutes in enlarging the nest,
after which she again closed it up. During the remainder of
that day we saw her frequently in the neighborhood but on the
fifth, sixth, seventh, and eighth she visited the nest only once
each morning and then disappeared. After the eighth we saw
her no more and the nest had not been reopened when we left
our country home on September tenth.

We could usually enter into the feelings of the Ammophilae
and understand the meaning of their actions, but we were puz-
zled once, when we saw an urnaria that had stored her second
caterpillar and closed her nest permanently, spend the rest of
her morning in hunting. Why in hunting? She had not dug
a nest, she could not lay another egg at once, she did not want a
caterpillar, for when we offered her one she stung it and then
left it lying on the ground. The sun was bright, the sorrel-
blossoms invited her. Surely it would have been the part of a
rational wasp to have passed the rest of the day in feasting and
fun.

We have said that urnaria stores two caterpillars but this
rule is not without its exception. It was on the last day of the
summer, that on a visit to our dear and fruitful potato field, we
came upon the Grandmother of all the Ammophiles, for so we

AMMOPHILA AND HER CATERPILLARS. 29

named lier on account of her immense size. Twice as large as
an ordinary iirnaria, she made, when flying, a loud hum that
at once attracted attention. She was just completing and clos-
ing her nest and we determined to watch and see what kind of
a victim she would bring in, as it seemed improbable that this
great creature would content herself with the ordinary fare of
the species. The opening to the nest measured half an inch in
diameter.

It was eleven o'clock when she flew away. At haK past
twelve she reappeared, coming from the direction of the woods,
opened her nest and took out a few more pellets. Then she flew
to a bush which grew against the fence, three feet away, and
following her quickly we saw an immense green caterpillar
placed high up on a branch. It must have taken both strength
and perseverance to drag this heavy weight so far from the
ground. She seized it at once and carried it down, not flying,
as these wasps sometimes do when they are descending with a
burden, and then dragged it into her nest, where it fitted rather
tightly. This nest was so shallow and so obliquely directed that
the caterpillar was plainly visible after it had been taken in.

After she had laid her egg she crawled out, getting past the
caterpillar with some difiiculty, and closed the nest. There was
certainly no room for any further store of provisions and from
the size of the caterpillar we judged that it would furnish suffi-
cient nourishment even for the offspring cf this wasp. We
were, therefore, not surprised, upon opening the nest two days
later, to find that nothing more had been brought. We have
said that the wasp larvae spend from six days to two weeks in
eating. To be more exact, all that we watched, with the ex-
ception of the one which developed from the egg of this big
wasp, ate from six to eight days and then spun their cocoons, but
this one seemed determined to reach the size of its mother and
ate continuously for fourteen days. Of course long before this
time had expired the remnant of the caterpillar had become a
dry, dark-colored mass which looked little likely to tempt the
appetite, but the great larva at-e away with unabated relish.

30 THE SOLITARY WASPS.

gradually acquiring the color and almost the thickness of the
caterpillar it had destroyed.

Westwood states that Anmiophila, when she has captured her
prey, walks backward, dragging it after her,* but in all the cases
that came under our notice she walked forward, the caterpillar
being grasped near the anterior end, in her mandibles, and either
lifted above the ground or allowed to drag a little if long and
heavy. It is usually held venter up, but in one case, in which
the wasp, while carrying it to her nest, frequently laid it down
and picked it up again, it was held with the venter down or up
indifferently.

The all-important lesson that Fabre draws from his study of
the Ammophiles, is that they are inspired by automatically per-
fect instiircts which can never have varied to any appreciable ex-
tent from the beginning of time. He argues that deviation from
the regular rule would mean extinction. For example, if the
wasp should sting ever so little to one side of the median line the
prey would be imperfectly paralyzed and the egg would conse-
quently be destroyed; or a sting in the wrong place might cause
the death of the caterpillar and thus the death of the wasp larva,
which, he thinks, can only be nourished by perfectly fresh food.

The conclusions that we draw from the study of this genus
differ in the most striking manner from those of Fabre. The
one preeminent, unmistakable and ever present fact is variabil-
ity. Variability in every particular, — in the shape of the nest
and the manner of digging it, in the condition of the nest
(whether closed or open) when left temporarily, in the method
of stinging the prey, in the degree of malaxation, in the man-
ner of carrying the victim, in the way of closing the nest, and
last, and most important of all, in the condition produced in the
victims of the stinging, some of them dying and becoming "ver-
itable cadavers," to use an' expressive term of Fabre's, long be-
fore the larva is ready to begin on them, while others live long
past the time at wldch they would have been attacked and de-
stroyed if we had not interfered with the natural course of

♦Introduction to Modem Classification of Insects, ^ol. II., p. 189.

AMMOPHILA AND HER CATERPILLARS. 31

-events. And all tliis variability we get from a study of nine
wasps and fifteen caterpillars!

In his chapter on "Methode des Ammophiles" Fabre says that
•each species has its own tactics, allowing no novitiate. "Not
one could have left descendants if it were not the handy work-
man of today. Any little slip is impracticable when the future
of the race depends upon it." And yet we find that the prey
may be stung so slightly that it can rear and wriggle violently
or so severely that it dies almost at once, and in neither case is
a break made in the generations of the Ammophiles, since in
the former, the e>g^ or larva is so firmly fastened as to keep its
liold, while in the latter the dead and decomposing caterpillar is
eaten without dissatisfaction or injury.

l^ov do we, in gathering evidence for the evolution of the in-
stincts of these wasps, need to rely entirely upon our own obser-
vations. Fabre himself gives many facts which point in the
•same direction, but he draws a line between those actions which
are the result of mechanical and unvarying instinct and those
which come within the sphere of reason, and in relation to which
the insect must consider, compare, and judge. Yet this line,
even in the light of his own work, is so extremely variable, need-
ing readjustment with every new species and often among the
individuals of the same species, that it loses for others the
meaning which it has for its author. He himself speaks of
■certain individuals of the genus Sphex which refuse to be duped
when he withdraws their prey to a distance. These, he says,
■are the elite, the strong-headed ones, which are able to recog-
nize the malice of the action and govern themselves accordingly,
hut these revolutionists, apt at progress, he goes on to say, are
few in numbers. The others, the conservators of old usages and
'Customs are the majority, the crowd. Yes, but is it not always
the strong-minded few that direct the destiny of a race?

Darwin's suggestion in relation to the stinging instincts of the
^solitary wasps is that they originally killed their prey by sting-
ing them in many places on the lower and softer side of the body
(this habit of killing outright is still seen in Bemhex and many

32 THE SOLITARY WASPS.

other genera), and that to sting a certain segment being found
the most successful method, this habit was inherited like the
tendency of a bull dog to pin the nose of a bull, or of a ferret to
bite the cerebellum ; and that the next step in advance was to
prick the ganglion only slightly, thus giving the larvae fresh
instead of dried meat.* It seems to us more probable that we
have in these instincts examples of the action of natural salec-
tion, the primary advantage of the use of the sting being to re-
duce the prey to helplessness. Our AmmopJiila, with their
many-ganglioned caterpillars, have been carried some steps fur-
ther, and if, as may be possible, those larvae which have pro-
vided for them caterpillars that cannot move and that yet are
alive and fresh, derive any advantage from these conditions,
the present variable state of things may merge into one in which
the instinct will be better adjusted, approaching and perhaps
finally reaching that which Fabre finds in the species which he
has observed; but at present, speaking for A. urnaria, we may
say that this instinct, wonderful, complex and difficult to ex-
plain as it unquestionably is, is still far from being exact, either
in its methods or in the results obtained.

*Life and Letters, Vol. II., p. 420.

THE GREAT GOLDEN DIGGER. 33

CHAPTEE II.
THE GREAT GOLDEN DIGGER.

Sphex iclineumonea Linn.
PI. II., fig. 4; XL, fig. 1, XII., figs. 1, 2.

Tliis -wasp is one of our most beautiful species, its great size
and its briUiant color, as it flies among tbe flowers, serving to
make it well known to all observers of nature. During the later
part of July, all through. August, and even in the early days of
September it is commonly found at work making or storing its
burrow. It is rare in our garden, however, and we thought our-
selves fortunate in being able to keep track of one individual
from the making to the closing of the nest. Although large
and powerful it is gracefully formed. In color it is brown, with
two pairs of yellow spots on the abdomen. (PL IL, fig, 4.)

On the morning of the third of August, at a little after ten
o'clock, we saw one of these hunters start to dig a nest on the
side of a stony hill. After making some progress in the work
she flew off and selected a second place where she dug so per-
sistently that we felt confident that this was to be her final
resting-place, but when the hole was two and one-half inches
deep it, too, was deserted. Again our wasp chose a spot and
began to burrow. She worked very rapidly and at twenty min-
utes before twelve the hole was three inches deep. At high
noon she flew away and was gone forty minutes. The day was
excessively hot, about 98° Fahr., and we ourselves were only de-
terred from taking a noonday rest by our fixed determination
not to leave the place until we had seen all that there was to be
seen in the manceuvres of iclmcumonea. On returning she ap-
peared very much excited, fairly quivering with vitality as she
resumed her work. She came up backward carrying the earth
3

34 THE SOLITARY WASPS.

with her mouth and anterior legs, and went back from the open-
ing some little distance, when it was dropped and she at once
went in again. While in the burrow we could hear her hum-
ming, just as the Pelopaei do when, head downward in the wet
mud, thej gather their load for nest-building. In five or six
trips a little mass of earth would accumulate, and then she would
lie quite flat on the heap and kick the particles away in all di-
rections. As the work progressed the earth was carried further
and further away before it was placed on the ground, and as
she backed in different directions the material brought out was
well spread about from the down-hill side of the nest. Some-
times she would spend several moments in smoothing the debris
all around so that the opening presented much the appearance
of an immense ant-hill, only the particles were much larger.
During the first hour that we watched her she frequently turned
directly toward us, and, sometimes remaining on the ground and
sometimes rising on her wings to a level with our faces, appeared
to be eyeing us intently for four or five seconds. Her attitude
was comical and she seemed to be saying, "Well, what are you
hanging around here for?"

As the afternoon wore on she worked more calmly and her
fidgety and excited manner disappeared, the excavation progress-
ing steadily until half -past three. At that time she came out
and walked slowly about in front of her nest and all around it.
Then she rose and cii-cled just above it, gradually widening her
circle, now going further afield and now flying in and out
among the plants and bushes in the immediate vicinity. The
detailed survey of every little object near her nest was remark-
able and not until her tour of observation had carried her five
times entirely around the spot did she appear satisfied and fly
away. All her actions showed that she was studying the local-
ity and getting her bearings before taking her departure. (PL
511., fig. 1-2.) A fact that impressed us very much was
that with the two nests that she had begun and then deserted
she had taken no such precaution, but simply came up and flew
off. Had she made up her mind, if we may be allowed to use

THE GREAT GOLDEN DIGGER. 35

the term, that the localities were in some way unsuitable and
that hence she had no occasion to return to them? Had she de-
cided, in the last instance, that she would return and so must
^•et her bearings? We wondered how far the different acts
were instinctive, or were, as Huber has it, an evidence of a "lit-
tle dose of judgment." Bates, in speaking of Monedula signa-
ta, says that he often noticed in taking a few turns about the lo-
cality of its nest and that he was convinced that it was doing so
for the purpose of getting its bearings. Belt, having described
how he fed a specimen of Polistes camifex with a caterpillar,
"which the wasp cut into two parts, goes on to say: "Being at
the time amidst a thick mass of fine-leaved climbing plant, it
proceeded, before flying away, to take note of the place where
it was leaving the other half. To do this, it hovered in front
of it for a few seconds, then took small circles in front of it,
then larger ones around the whole plant. I thought it had gone,
but it returned again, and had another look at the opening in
the dense foliage down which the other half of the caterpillar
la."* He then remarks that when the wasp came back for the
remaining half it flew straight to its nest without taking any
further note of the locality. Both of these wi-iters believe that
many of the actions of insects that are ascribed to instinct are
really evidence of the possession of a certain amount of reason-
ing power.

To return to our Spliex. When she flew away we naturally
supposed that she had gone in search of her piey, and we were
on the qui vive to observe every step in her actions when she
came home. Alas! when she came back half an hour later, she
was empty handed. She dug for four minutes, then flew off
and was gone two minutes, then returned and worked for thirty-
five minutes. Another two minutes' excursion, and then she
settled down to work in good earnest and brought up load after
load of earth until the shadows grew long. We noticed that on
"these later trips she flew directly away, depending upon her first
careful study of the suroundings to find her way back. At

*]Sraturalist in Nicaragua, p. 136.

36 THE SOLITARY WASPS.

fifteen minutes after five tlie patient worker came to the surface
and for tlie second time made a detailed study of the en^dron-
ment. She flew this way and that, in and out among the plants,
high and low, far and near, and at last, satisfied, rose in circles,,
higher and higher and disappeared from view. We waited for
her return with all the patience at our command, from fifteen
minutes after five until fifteen minutes before seven. We felt,
sure that when she came back she would bring her victim with
her and when we saw her approaching we threw ourselves prone
on the ground, eagerly expecting to see the end of the drama,
but her search had been unsuccessful, — she carried nothing. In
the realms of wasp-life disappointments are not uncommon, and
this time she had us to share her chagrin, for we felt as tired and
discouraged as she perhaps did herself. When we saw her en-
tering vsdthout any provision for her future offspring we w^ere
at a loss what to do next and it may be that this state of mind
was shared by her also, for she at once began to fill in the en-
trance to her nest. We now thought it time to act, and decided
to capture her, to keep her over night in one of our wasp-cages,
and to try to induce her to return to her duty on the following^
day. We therefore secured her in a large bottle, carried her to
the cottage, and having made every possible arrangement for her
comfort, left her for the night.

On the next morning, at half after eight o'clock, we took Lady
Sphex down to her home and placed the mouth of the bottle sO'
that when she came out she had to enter the nest. This she did,
remaining below, however, only a moment. When she came
up to the surface she stood still and looked about for a few sec-
onds, and then flew away. It surprised us that having been ab-
sent from the place for so many hours, she made no study of
the locality as she had done before. We thought it a very un-
promising sign, and had great fears that she was deserting the
place and that we should see her no more. One would need to
watch a wasp through the long hours of a broiling hot day to
appreciate the joy that we felt when at nine o'clock, we saw her
coming back. She had no difficulty in finding her nest nor did

THE GREAT O OLDEN DIGGER. 37

she feel any hesitation as to what ought to he done next, hut
fell to work at once at carrying out more dirt. The weather,
although still hot, had become cloudy and so threatening that
we expected a down-pour of rain every moment, but this seemed
to make no difference to her. Load after load was brought up,
until, at the end of an hour, everything seemed completed to her
satisfaction. She came to the entrance and flew about, now this
way, and now that, repeating the locality study in the most
thorough manner, and then went away. At the expiration of
an hour we saw her approaching with a large, light green
meadow-grasshopper, which was held in the mouth and supported
by the fore legs, which were folded under. On arriving the
prey was placed, head first, near the entrance, while the depre-
dater went in, probably to reassure herself that all was right.
Soon she appeared at the door of the nest and remained motion-
less for some moments, gazing intently at her treasure. Then
seizing it (we thought by an antenna) she dragged it head first
into the tunnel.

The laying of the eg^ did not detain her long. She was up
in a moment and began at once to throw earth into the nest.
After a little she went in herself and we could plainly hear her
humming as she pushed the loose material down with her head.
"When she resumed the work outside we interrupted her to catch
a little fly that we had already driven off several times just as it
was about to enter the nest. The Sphex was disturbed and flew
away, and this gave us an oportunity to open the burrow. The
grasshopper was placed on its back, with its head next to the
blind end of the pocketi and the legs protuding up into the tun-
nel. In digging out these nests we have found that by pushing
thei slender stem of a plant into the hole before the wasp fills it
up we are greatly aided in following the direction of the tunnel
and in finding the prey at the bottom. Before using tliis simple
device we often went astray and lost the nest.

We found that the egg of the wasp, which was seven milli-
meters long, and rather slender, was placed on the under face of
the thorax at a right angle to its length, and parallel with the

38 THE SOLITARY WASPS.

femur of the second leg. This leg had apparently been stung
so that it had swollen end folded over the free end of the eggy.
which was thus firmly held in place at both extremities.* Upon
examination we found that the abdomen of the grasshopper wa&
beating regularly and automatically but the closest observation
failed to discover any other movements nor would any part re-
spond when stimulated. At three o'clock in the afternoon we
found the abdomen still pulsating, and, in addition, that both
antennae moved several times w^hen we lifted off the cover of the
jar that contained the insect. On the next morning the gTass-
hopper was very lively, the antennae and labial palpi moving
without stimulation. It had passed faeces, and was able to lift
its abdomen, which was curved over toward the head, as it lay
on its back, frequently and with considerable violence. On the
next afternoon (August sixth) there Avas no change in the move-
ments but the egg was dead. On the seventh the grasshopper
responded to stimulation by a slight movement of the palpi and
the end of the abdomen. The pulsation of the abdomen contin-
ued until the afternoon of the eighth when it ceased, no effort
of ours succeeding in starting it again. The movements of the
antennae and palpi grew weaker and weaker on the ninth, and
on the morning of the tenth the insect was dead, a period of
five and a half days having elapsed since it was brought into the
nest. "We caused a wasp of the genus Polistes to sting a grass'
hopper of the same species on the under surface of the thorax.
The insect was paralyzed and died on the third day. In the
wasps studied by Fabre> the egg hatched in from three to four
days, and the grub ate from ten to twelve days before spinning
its cocoon. Probably 'wlmeumonea does not differ greatly from
the other species in these particulars.

We had not supposed that the digging up of her nest would
much disturb our SpJiex since her connection with it was so

*Fabre says that all of the three species of Sphex that he has studied
lay the egg on this identical place. He lays immense importance on
this point which seems to ns rather fanciful. He also noticed the
pulsation of the abdomen and the movements of the other parts.

THE GREAT GOLDEN DIGGER. 39

nearly at an end, but in this we were mistaken. When we re-
turned to the garden about half an hour after we had done the
deed, Ave heard her loud and anxious humming from a distance.
She was searching far and near for her treasure house, return-
ing everj few minutes to the right spot, although the upturned
earth had entirely changed its appearance. She seemed un-
able to believe her eyes, and her persistent refusal to accept the
fact that her nest had been destroyed was pathetic. She staid
about the garden all through the day, and made so many visits
to us, getting under our umbrellas and thrusting her tremen-
dous personality into our very faces, that we wondered if she
were trying to question us as to the whereabouts of her property.

Dr. Packard describes Sphex ichneumonea as nesting in
gravelly walks, where it digs to a depth of from four to six
inches, using its jaws and fore legs to do the excavating. While
the wasps that he observed completed the hole in half an hour,
ours was actually at work a little over four hours. Her nest,
as is shown in the drawing (PL XI., fig. 1), measured seven
and one-half inches to the beginning of the pocket, which was
three-quarters of an inch wide by one and one-half inches long.
The yellow-winged Sphex, a native of France, was found, by
Fabre to take several hours to make her nest, working in hard
ground, while another species, also studied by this distinguished
observer, dug in soft earth, either in the ground or in the
accumulations on the roofs of buildings, and completed her
work in fifteen minutes at the most. These variations in the
habits of closely related species should be carefully studied in
any attempt toward an explanation of their instincts.

Pabre's account of the genus Sphex, as it appears in Prance,
is most interesting. He says that the yellow-winged species,
living in colonies, first digs her nest and then secures her cricket,
which is brought, on the wing, to the neighborhood of the bur-
row, the last part of the journey being accomplished on foot.
The cricket is dragged by one of the antennae and is not left un-
til the nest is reached. It is then placed so that the antennae

40 THE SOLITARY WASPS.

reach precisely to tlie opening, and there it is left while the wasp
descends hun-iedlj into the depths of the burrow. In a few
seconds she reappears, showing her head outside, seizes the an-
tennae of the cricket and drags it below. These manoeuvres
are repeated with a striking degree of invariability. One ex-
periment of M. Tab re was as follows: As the Sphex descended
into the nest he took the cricket from the entrance and moved
it a few inches away. The wasp coming up, looked about with
astonishment, and seeing its victim too far away, came out,
seized it, and placed it again in the desired position. This done
it again descended, but alone. The same manoeuvre was re-
peated by M. Fabre, the same disappointment was exhibited by
the wasp on her return. The prey was again brought to the en-
trance of the burrow but she again went down without it. The
experiment was repeated again and again until the patience of
the observer was exhausted. He made the test about forty
times on the same individual but the tactics of the wasp never
varied.

The other Sphex (c:Jled by Fabre Sphcx languedocien,)
first secures her prey, which is too large and heavy to be
carried far, and then digs her nest in the neighborhood of
the capture. This being done she returns to her victim
and straddling it, drage it by one or both of the antennse.
Sometimes the whole journey is accomplished at once, but
oftener the wasp suddenly drops her burden and runs rapid-
ly to her nest. Perhaps it seems to her that the entrance is not
large enough to accommodate a creature of such size; perhaps
she imagines some imperfections of detail which would impede
the process of storing it up. The work is retouched, the door-
way enlarged, the threshold smoothed. Then she returns to her
booty and again starts with it. After a few steps the Sphex
seems to be seized with another idea. She has visited the door-
way but has not seen the interior. Who knows whether all is
well within? She drops her prey and again runs off. The
visit to the interior is made, more touches given, and once more

THE GREAT GOLDEN DIGGER. 41

she returns. Will the journey be accomplished this time? Im-
possible to say. Some wasps, more suspicious than others per-
haps, or more forgetful of the small details of architecture, to
repair their neglect or to clear up their suspicions, abandon their
booty five or six times in succession to retouch the nest or simply
to visit the interior. The prey, once brought to the nest, is car-
ried in without the preliminaries that are common to the other
species.

42 THE SOLITARY WASPS.

CHAPTEE III.

THE INHABITANTS OF AN OLD STU]\iP.

Rliopalum pcdicellatnm Pack., and Stigmus Americanus Pack.

In a search for tlie nests of one of our garden wasps we found,
in the woods to the north of the fence, and not far distant from
it, an old, weather-beaten stump which was riddled with holes
both large and small. The large ones were evidently the pas-
sage ways of ants and were in constant use. The small ones
seemed id be uninhabited but thinking that possibly they might
contain the nests we were in search of, and hoping that if we
watched long enough we might see our wasps flitting in and out,,
we settled ourselves close by. We were resolved to stay as long
as was necessary and we blessed the fate that made it our duty
to sit on the grass under the shade of a wide-spreading oak rather
than in the distressing glare and heat of the garden, for this
was on the tenth of July, and the weather was what the farmers-
call "seasonable."

Twenty, thirty, forty minutes passed. Our eyes ached with
persistent gazing and we had nearly made up our minds that the
likely looking little holes were untenanted, when lo ! a tiny wasp,,
carrying something which we could not see distinctly, darted in-
to one of them. It was gone so quickly that we could not be
sure that it was the species we were looking for, and when it re-
appeared, after two or three minutes, we saw that it was not.
This point being determined we watched the hole with re-
doubled interest.

It was wearisome work, for the wasp stayed away a long time
and we dared not let our gaze wander lest she should slip in
without our knowledge. At the end of thirty-five minutes she

INHABITANTS OF AN OLD STUMP. 4a

returned, but again we failed to see what she carried. She flew
with great rapidity and we scarcely caught sight of her before
she vanished into her nest. We could not but wonder at the
ease and certainty wdth which she recognized her own doorway
among the hundreds of holes on the side of the stump. This
power of localization, wliile it is one of the most common among
wasps, is surely also one of the most remarkable.

Our little Rliopalum pediccllatum, for that proved to be her
name, made six more journeys within the next two hours. At the
end of this time we opened the tunnel, and, after a great deal
of sawing and cutting, succeeded in finding the nest five inches
from the surface. It was nothing but a slight enlargement of
the gallery, in the soft decaying wood. In it we found thirty-
three gray gnats of the genus Chiroiwmus, all of them being
dead excepting tw^o. On one of the dead ones was the eggy,
which had probably been laid within a few hours.

The egg hatched two days later, on July twelfth, but on the
fifteenth the larva died. By this time many of the gnats looked
very dry, although we had tried to an-ange for both moisture
£nd ventilation by packing the bottom of the tube with pith
and covering the top with muslin.

Further watching gave us one more wasp of this species, in
the same stump. This time the nest was only two inches from
the surface. It contained four dead gnats and two live ones,
but no egg, showing that the egg is not always laid on the first
ones stored.

Much later in the season, toward the end of August, we found
another species of Rhopalum which proved to be new, and for
which Mr. Ashmead has proposed the name rubrocinctmn since
it wears a red girdle around the front end of the abdomen, being
otherwise dressed in black like pedicillatum. It makes its home
in the stalks of raspberry bushes. We opened a stem which
contained thirteen compartments, separated by partitions of
pith. These were filled, with black, gray, and green gnats,
which were packed in so closely that they were doubled over
and pressed all out of shape. Each cell contained from twenty-

44 THE SOLITARY WASPS.

five to tliirtj gnats. In some of them were cocoons, in others,
larvae, and in one, an egg. The gnats were very carefully ex-
amined, and all of them, from the cells that had been filled last
as well as from those provisioned earlier, were dead.

Other species of Eliopalmn are said to prey upon spiders and
aphides.

Stigmus mivericamis Packard.

Rhopahwi w^as not the only wasp that had found a home in
the old stump. By dint of patient watching we discovered yet
other tiny black creatures going in and out of one of the little
holes. These wasps, which were scarcely more than one-eighth
of an inch in length, proved to belong to the species Stigmus
americamts, and we soon found that they were busily collecting
aphides which they probably took from the choke-cherry bushes
on the other side of the fence, since their journeys only occupied
three or four minutes. We could see that three wasps were
using the same galleiy, all working together in peace and har-
mony. The hole appeared to be an old one, but whenever they
came out they earned grains of pith, thus enlarging it to suit
their necessities.

After having watched their goings and comings for several
hours we determined to open the nest. Following the tunnel
with some difficulty for four inches we found a depression. In
this was a curious looking mass which proved, upon close ex-
amination, to be made up of grains of pith mixed with apliides.
To the ventral surface of one of these an egg was attached.
Half an inch further on was another depression holding a simi-
lar mass, the egg, in this case, ha^ang been placed upon the dor-
sal surface. There were, in all, forty-five apliides, about equal-
ly divided between the two nests. We tested them very care-
fully and found that they were all dead. The gallery then,
must have been a general hall or passage-way used by several
individuals. We had seen three wasps and we found only two
nests, but probably we missed the third one amid the difficulties
of sawing and cutting.

Hoping to rear the larvae we preserved the contents of both

INHABITANTS OF AN OLD STUMP. 45

nests, but we were successful witli only one of them. We had
taken the eggs on July eleventh, and on the following day one
of them hatched. By this time many of the aphides had dried
up and were turning yellowish. On July fifteenth there were
only two or three green ones left, all the rest being brown or
black, but the larva continued to eat contentedly. On the
twenty-first the aphides were all dry and the larva now ate only
the inside, leaving the shell. On the twenty-sixth it spun a
light yellow cocoon within which it remained until September
second. On that day there came forth not a wasp at all, but a
brilliant green Chrysis fly (Omaliis corrusccuis) which we had
often seen in close attendance upon Diodontus americanus. The
egg of the wasp would probably have been laid after the nest
was fully provisioned, but since the fly had the start the wasp
larva would have had small chance of finding a sufficient food
supply.

The only notes that w^e find concerning this genus are one in
Mr. Ashmead's paper which says that Stigmus argcntifrons
provisions its nest with aphides, and one in Westwood stating
that Mr. Kennedy discovered the cells of Stigmus troglodyies
in hollow straws of a thatch, the cells being filled with minute
insects, v/hich appeared to be the larvas of a Thrips, as many as
fifty being found in one cell.*

^Modern Classification of Insects, Vol II., p. 195.

46 THE SOLITARY WASPS.

CHAPTER IV.

THE TOILERS OF THE NIGHT.

Crahro stirpicola Packard.
PI. II., fig. 5; XL, figs. 6, 7.

We have, in this locality, a number of species of the genus
XJrabrOy several of which are quite common. All, so far as we
liave observed them, make their nests in the stems of plants, be-
ing especially common in the stalks of the raspberry and the
blackberry. Our Crahro stirpicola is about one-quarter of an
inch long, and is black with yellow legs, yellow bars on the
thorax and interrupted yellow bpjids on the abdomen. (PL 11. ,
fig. 5.) It is seen in numbers, through the middle of July, fly-
ing about in a leisurely way, but it is only toward the end of the
month, or in the early days of August that they settle down to
the work of making their homes. On the afternoon of July
twenty-seventh, after some very lively work in the heat of the
day, we walked down to the berry garden at half past five
o'clock, rather to rest ourselves than with the thought of under-
taking anything new ; but a wasp-hunter cannot afford to choose
his own hours and we thankfully accepted the sending of for-
tune when we came upon a Crahro busy at work in digging out
her nest. She had only begun to excavate and had reached a
length just equal to that of her own body. Her manners were
an agreeable contrast to those of the wasps that we had been
watching through the day. The feverish excitement of their
ways seemed quite in keeping with the burning heat of noon,
while Crahro' s slow and gentle movements harmonized perfect-
ly with the long shadows of evening. To fully appreciate the
difference between Pompilus or Amtitophila and Crahro it is
necessary to see them at work. The one is the embodiment of

THE TOILERS OF THE NIGHT. 47

^11 that is restless, vying with the humming-birds in swiftness
and energy, while the other is calm, quiet, and stately in all that
she does.

Some ten feet away was a second stirpicola at work, and this
one, to judge from the depth to which she had penetrated, must
have been at work for about two hours. We watched them
both and saw them bring up load after load of pith. They bit
out the pellets with their mandibles and passed them back be-
tween the legs and under the body until a quantity had accum-
ulated above the tip of the abdomen. They then walked back-
ward up the stem and thus pushed out the mass as they came to
the top. Often they used the hind legs to assist in getting it out
of the way, sometimes kicking it to a little distance. Once in
-every two or three trips they would come out far enough to ex-
pose part of the thorax. They appeared and disappeared with
the regularity of a machine, never stoping to rest.

We remained with them until seven o'clock when we placed a
long large bottle over each stem (PL XL, fig. 7), in such ai way
that while it did not interfere with the work of the wasp it
caught the chips of pith as they fell out. At the end of an hour
we noted the amount of accumulation in the tube and thus had
a measure of their rate of work. The drawing gives an idea of
the arrangement of the tube on the stem. When we left them
they were still digging and delving.

At half past nin'fe we took a lantern and went down to visit
our charges. We expected to find them at rest and asleep but
on the contrary they were working as busily as ever, and upon
examining the measuring glasses we found that they had not
paused since we left them. We measured the depth of the
■debris in the bottles and then emptied them for the night. At
four o'clock on the next morning we went to the garden and
were much surprised to find that the two wasps h?.d worked
w^'thout intermission throughout the night. Indeed they
seemed to have shortened a little the time that it took to make
a round trip down the gallery and up to the opening again, since
there was more pith in the bottles than we could have expected

48 THE SOLITARY WASPS.

if they had worked only at tlieir former rate. !N"eitlier the
coolness of the air nor the darkness of the night had made the
slififhtest difference to them. After watching them a few min-
utes and marvelling at their powers of endurance, we cleared
out the tubes and returned to bed. At half past eight we found
them still at work. Unlike us, they had taken no morning nap,,
but had gone on with their tunneling in their usual steady way.

From this time their ways diverged and they must be de-
scribed separately. At nine o'clock the one that we had first
seen came up to the opening walking head first, and flew off, re-
maining away seven minutes. When she returned she at once
resumed her work and kept at it without a pause until two in
the afternoon. At this hour she went away and we never saw
her again. "We suppose that she was killed, for it seems im-
probable that so faithful a creature could have deserted her
half -finished home. Pompilus quinquenotatns often deserted a
partly finished nest for some more enticing spot, and Sphex
started several excavations before making a final choice, but we
cannot believe that there was anything fickle about Vrahro.

The second wasp came up head first to the entrance of her
hole at two minutes after nine, as though she had been influ-
enced, in some subtle way, by her neighbor's example, but after
looking about for a moment she went back. She repeated this
observation several times and finally, at twenty-five minutes
after nine, came out and flew to a leaf near by. Then she cir-
cled around, alighting a number of times, and, at last, departed.
Her stay was brief for at just thirty-five minutes after nine she
returned and at once settled down to her work.

We now began to make notes as to the length of time that it
took her to go down and bring back her load. We timed her
again and again and found that she was remarkably regular,
each of her trips occupying from forty-five to fifty seconds.

All that day we kept her under strict surveillance and never
once did she suspend her operations either for rest or refrech-
ment. Late in the afternoon while we sat watching her as she
appeared and disappeared with almost the regularity of clock

THE TOILERS OF THE NIOHT. 49

work, we found it diiEcult to realize that tlie patient little crea-
ture liad been at work for more tlian twenty-four hours, with
only one brief intermission. Without hurry or flurry she kept
at her task, reminding us, in her business-like ways of the social
wasps of the genus Yespa. "When we left her, at dusk, we at-
tached the recording tube to the stem, and at ten o'clock in the
evening we found that she had not stopped working. We
emptied the glass and left her.

At seven o'clock in the morning of July twenty-ninth we paid
her a visit, and could scarcely believe the testimony of our
lenses when we saw that the record was one of unceasing toil
through the long hours of the second night. We began to won-
der if she would ever finish her task. Wonderful though she
was we had grown a little weary of our long session of watch-
ing. We had been glad that she worked through the first night;
it was creditable to her and interesting to us, and we admired
her even more for sticking to it through the second, but when
it looked as though we might have to remain by her side through
another long day, watching an endless series of loads as they
were carried out, we confess that we thought she was rather
overdoing it. Gradually, however, she slowed up her work,
taking two or three minutes to make a journey down and up.
At last, at just nine o'clock, her head appeared at the top of
the stalk, and after a slight hesitation she flew away. The nest
was completed.

We have studied hymenoptera for a number of years and we
feel that we are on terms of more or less intimacy with many of
the species, but never before have we known one to work after
day was done. We have often gone out with a lantern at bed-
time for a tour of inspection among our nests and have always
found the inhabitants quiet and presumably asleep. The social
wasps are very industrious but during the hot nights of July
they are to be seen clustered together on the outside of their pa-
per nests in deep repose, and although the Vespa wasps that nest
in the ground sometimes come home late in the twilight we have
never seen them work after it was really dark, Polistes fusca
4

50 THE SOLITARY WASPS.

may be said to share oiir cottage, so thickly does she hang her
combs under the shelter of our porches, and from observations
taken at all hours we know that she is quiet through the night.
Sir John Lubbock in "Ants, Bees, and Wasps," speaks of the
great industry of wasps. He has known them to work from
early morning until dusk without any interval for rest or re-
freshment; but here was our little Crahro toiling from three in
the afternoon of July twenty-seventh, through that night and
the day and night following until nine o'clock on the morning
of the t^\enty-ninth, — a period of forty-two consecutive hours
with one intermission of ten minutes on the morning of the
twenty-eighth. Surely she takes the palm for industiy, not only
from other wasps but from the ant andj the bee as well.

The nest was completed but the work of storing it remained
to be done. The wasp flew away at nine o'clock, and ten min-
utes later came back with something, we knew not what, for she
dropped into her hole so quickly that she was oat of sight almost
before we knew she was there. Two minutes later* she came up
and was off again. This time she was gone twelve minutes and
when she came back we were again baffled in our effort to see
what she was carrying. When she came out she alighted upon
a leaf and attended to her toilet, cleaning both body and wings
by rubbing them off with her hind legs, and from this time on
she never started on a hunting expedition without paying this
attention to her personal appearance. On her third trip she
was gone twenty minutes. We tried to delay her entrance,
when she returned, in order to see what she was bringing in, but
did not succeed. In another twenty minutes she came home
again and this time we saw that she was carrying a small fly.
Her record for the rest of the morning is as follows:

Eetumed. Left.

10.28 • 10.30

10.42 10.44 ;.

11.1 11.3

11.6 11.7

11.23 11.26

'- 11.34 11.35

THE TOILERS OF THE NIGHT. 51

Some of these last journeys were merely short flights around
her domicile, and not for the purpose of seeking prey.

We now left her but came back at half past two in the after-
noon. She was working, and she kept up her goings and com-
ings until four o'clock when she suspended operations for the
day. On the next morning we were called away and know
nothing of what she did, but on the following day, July thirty-
first, we resumed our observations. She worked hard all the
morning, but in the afternoon her trips were few and were made
at long intervals. On the morning of August first she worked
from eight to nine, when she departed and never returned. We
watched for her, at intervals, all through that day and the
next, when we were forced to conclude that our faithful little
worker had fallen a victim to some bird or beast. We did not
disturb the nest until the fifth, when we cut the stalk and ex-
amined iL.

We found that the tunnel was thirty-nine centimetera in
length. This was a long distance for her to excavate, and, all
things considered, her progress had been rapid. We have
opened a number of stems that had been stored by this species
and all the excavations were from thirty to forty centimeters
in lengthy the width of the gallery being about three and one-
half millimeters, while on each side there was from one to one
and one-half millimeters of pith that had not been cut away.
Of course these points varied with the diameter of the stem and
also with the size of the worker.

We found that our little stirpicola had stored one cell, had
laid an egg, and had built a" partition of pith across the stem as
a floor to the second cell, before her untimely taking off. Had
she lived, ten or twelve cells would have been stored, one above
the other. The completed cell contained a larva and parts of
eighteen flies of different sizes, four species being represented,
Opthirsia puncUpennis Wlk., Anthomyia sp., Calliphora voni-
itaria, and another that we could not identify. The flies had all
been attacked by the larva, the abdomens of some and the tho-
races of others having been eaten. The larva continued to eat

52 THE SOLITARY WASPS.

■until the seventli and then spun its cocoon. (PL XI., fig. 6.)
If we suppose that two days passed before the hatching of the
egg the larval life lasted for six or seven days.

As the flies in the nest were all partially destroyed we know
nothing of their condition when they were brought in, but dur-
ing the summer we took many stalks which had been filled by
stirpicola and made notes on the state of the contents. A de-
scription of one of these will serve as an example of all the rest.

On August ninth we opened a stalk which had been partly
filled. The upper cell had just been stored, no pith partition
having been made above it, and no egg yet laid. It contained
twenty-three flies of the species Opthirsia pinwUpennis, all of
them dead, though plump and fresh. We examined them care-
fully but they had been killed, not paralyzed. They had been
packed in very closely. The cell just below contained twenty-
two flies of the same species, the larva having just begun to eat.
All of the flies were dead. We took them as well as those of the
first lot and examined them, one by one under a two-thirds ob-
jective, lest there should be some mistake as to their condition.
The third cell contained twenty-two flies which were dead, as.
was also the larva, which had eaten only five abdomens. In
the fourth and last cell were twenty flies, all dead. The larva
had eaten parts of ten of them and was still at work.

In almost every instance the flies were all dead although once
in a long time we found one which gave a slight response to
stimulation. In many cases we found the larva eating them
after they were dry: thus the evidence of stirpicola still further
confirms us in our behef that the health of the growing larva does-
not at all depend upon its being furnished with fresh food.

All the pupae that we have kept have wintered in the cocoon
and have come out in the spring.

TWO SPIDER HUNTERS. 53

CHAPTER V.

TWO SPIDER HUNTERS.

Stinging Habits of ^alms conimts Say.

At noon on the third day of August we saw this little black
wasp hunting for prey. (PI. XIII., fig. 2.) She was on the
ground, running around and around the baee of a weed, the
place seeming to interest her greatly. Before long she discov-
ered a tiny male Lycosid and dashed at it, but the spider es-
caped. Apparently accustomed to such mishaps she began to
move very rapidly in a circle around the place where she had
lost her prey. She was greatly excited and moved with mar-
vellous celerity, but never once used her wings. A¥e have one
wasp {Pmnpilus quinquenotahis) whose movements suggest a
tornado, but this new depredator had the ways of a whirlwind.
As the circles narrowed she again caught sight of her victim and
made another dash but met the same fate as before. The Lycosid
was, in his way, quite as much of a runner and jumper as his
enemy and the contestants were well matched. Four times
in succession the wasp attacked but failed to grasp her victim,
but at last she succeeded and the two rolled over and over in
deadly embrace. Lest they should escape we placed our collect-
ing bottle over them and a,t this they separated, but as soon as
the glass, with them in it, was lifted up, the wasp threw herself
upon the unfortunate spider, seized him by the head, and bend-
ing her long slender body around and underneath thrust her
sting into the middle of the underside of the cephalothorax.
Almost instantly the spider collapsed. As we turned the glass
they fell apart, and again she dashed at her victim and with as
much ardor as before gave a second thrust after the manner of
the first. She then seized a leg and, moving backward like
Pompilus, began to drag her booty about.

54 THE SOLITARY WASPS.

Full of excitement we hurried about and caught another spi-
der, a female of the same genus but of a different species.
Would she take it? ISTot at all. She had her preferences and
was too good a systematist, as Fabre would say, to be confounded
by such a procedure. Again we rushed oft' and hunted over the
field unt'i we caught sight of a male of the species that she had
just taken. These little spiders run like lightning and are very
difficult to catch, but after a long chase he was captured and we
were ready for our second experiment. Thirty minutes had
passed since we left the wasp and we feared that her zeal for
game might have abated but as we put the spider in at one end
of the glass she recognized it from the other, pounced upon it,
and laying hold as she had before, delivered her sting to one side
of the middle of the ventral face of the thorax. We were hold-
ing the glass so that the combatants were in full view and the
whole affair was w^atched from step to step. This was the third
time that we had seen the sting given but we wanted further
evidence. We shook the two apart, and for the fourth time saw
this enemy of the arachnids do her deadly work.

Thus we learned the method of Saliiis in capturing her prey,
but we were still in doubt as to the effect of the operation just
performed under our eyes. Was it a dead body that she was
dragging about the glass or had her cunning reduced the poor
little spider to an inert mass of living matter, paralyzed, not
killed? Both of the limp Lycosids were submitted to a care-
ful examination. We tested their legs and stimulated their
falces but there were no responsive twitchings and after patient
study we concluded that both were dead. At evening we ex-
amined them again "with the same result. On the next day and
the day following we looked for signs of life but failed to find
them. The thrust of the wasp was fatal — it is not a mere hurt
that she inflicts but a death-blow. What shall we say of her?
that she is a mere butcher, and not the skilled operator that
we expected her to be? For our part we make no accusations
nor do we propose to intrude our notions into her affairs. Her
ways are doubtless the fittest for her purpose and to call the killer

TWO SPIDER HUNTERS. 55

brutal, or the paralyzer cruel is to do a wrong to tlie whole race
of wasps. It may be that other species of 8 alius deal differ-
ently with their yictims, just as the French Pelopaei always kill
their spiders while ours often only paralyze, but S. cordens gives
a fatal thrust.

At another time we saw one of these little wasps running
backward with a small Lycosid in her mandibles. She dropped
it repeatedly to rush about as though looking for something.
Soon she came to a small fresh looking hole which ran down
obliquely and into this she backed with the spider. Half an
hour later she came out and we then attempted to open the nest,
but the tunnel ran into a large cavity that had been filled by a
piece of decaying wood and we could not trace it.

Aporus fasciatus Smith.

This is a dark gray species and is less than half an inch in
length. (PL XIII., fig. 5.) We were working one day in the
melon field when we saw one of these little wasps going back-
ward and dragging a female of Maevia vittata which was much
larger than she was herseK. She twice left it on the ground
while she circled about for a moment, but soon carried it up
onto one of the large melon leaves and left it there while she
made a long and careful study of the locality, skimming close
to the ground in and out among the vines; at length she went
under a leaf that lay close to the ground and began to dig. After
her head was well down in the ground we broke off the leaf
that we might see her method of work. She went on for ten
minutes without noticing the change and then, without any
circling, flew off to visit her spider. When she tried to return
to her hole it was evident that some landmark was missing.
Again and again she zig-zagged from the spider to the nesting-
plac«, going by a sort of a path among the vines from leaf to
leaf and from blossom to blossom, but when she reached the
spot she did not recognize it. At last we laid the leaf back in its
place over the opening, when she at once went in and resumed
her work, keeping at it steadily for ten minutes longer. At

56 THE SOLITARY WASPS.

this point she suddenly reversed her operations and began to
fill the hole that she had made, kicking in the earth until the
entrance was liidden. She then glanced at the spider, selected
£1 new place and began to dig again. Surprisingly large pellets
of earth were carried out, backward, and loose dirt was kicked
under the body by the first legs. At the end of two or three
minutes she paused and remained perfectly still for a time. She
was considering the situation. Her conclusion was adverse to
the locahty for she soon filled in the hole, looked once more at
the spider and started a third nest in a new place. This in
turn was soon abandoned as was also a fourth. The fifth begin-
ning was made under a leaf that lay close to the ground, so that
we could not see her at all. We had now watched her for an
hour in the intense heat of noonday and most devoutly did we
hope that she was suited at last, but no — after twenty minutes'
work this place also was abandoned and a sixth nest started.
This, however, was the final choice and after forty-five minutes
spent in digging it was completed. As the spider was brought
toward the nest it was left again and again while the nervous
little wasp flew to the hole, went in, examined and came out
again. At last she backed in, caught the spider by the ab-
domen and dragged it down. It was too big — the head stuck
in the hole; but she pulled from below while we pushed gently
from above and it slowly disappeared. When she came out we
opened the nest and took the spider. The egg was fastened to
the middle of the left side of the abdo-men. This one, as was
also the case with a second and third afterward taken from
fasciatus, was much less affected by the poison than is usual
among the victims of soKtary wasps, moving from the time it
was taken, without any stimulation, and improving rapidly from
day to day. Our second spider appeared to be blind, and died
upon the sixteenth day, while the third had entirely recovered
by the seventeenth day after it was stung, and was released.
Fasoiatus, then, probably depends upon packing her victim in
tightly to keep it quiet.

It was three days and a half before the egg that we had taken

TWO SPIDER HUNTERS. 57

hatched. The larva developed rapidly retaining its hold at the
spot to which the mother had attached it. The spider remained
alive for six days, and the larva continued to grow for two days
longer when it died also, being at the time about two-thirds
grown. We had great trouble in protecting our growing larvae
from the inroads of fungi and this was one of the many that
perished from that cause.

The next example of fasciatus that came under our notice was
a remarkable contrast to the one that we have just described,
being as slow and dignified as the other was nervous and hurried.
She chose a place and kept to it, her steady labor being only
interrupted by occasional visits to the spider, but it took her
fifty minutes to complete the nest. When finished it was a
small gallery running down obliquely for an inch and a half
into the ground.

The thi-ee spiders taken from fasciatus were all Attidae but
represented three different genera, Phidippus, Attus, and
Maevia.

The one habit that this species can claim as peculiar to itself
is that of filling up the partly made nests that it is about to
abandon. We have never seen the sense of order carried to so
high a point in any other wasp.

Our observations on fasciatus were made between July
thirtieth and August twenty-fifth.

58' THE SOLITARY WASPS.

CHAPTER YI. ;

ajnt island settlement*.
Benibex spinolae St. Fargeau.
Plates n., fig. 6; VL; XL, 4.

"When wie found tliat our field of work was so ricli in material
that we could not possibly do it justice we brought the children
of the family on to the ground as assistants, and it is to our boy
George that we owe the discovery of the Bemhex colony. On
returning from an expedition to an island in the lake close by,
he reported that he had found a lot of bees or wasps, he did not
know which, and upon going to investigate the matter we found
a bare space of soft, rich earth, about eight feet wide by ten feet
long, fairly riddled with the holes of Bemhex spinolae.

These wasps are about three-quarters of an inch long and are
broad, heavy and somewhat clumsy, being shaped much like
bees. In color they are black, banded with bluish white. (PI.
If., fig. 6.) On this, our first \dsit, the weather was hot and
sunny and the gTound as well as the air above it was alive with
the large, showy wasps. Our arrival on the scene was the sig-
nal for a general hubbub. Evidently we were not personae
grata e to their majesties, for with a most intolerable buzzing
they darted at us on all sides at once, chasing us for some dis-
tance as we retreated, and when they turned back and left us in
peace we were surprised to find that no wounds had been in-
flicted. The battle had been all sound and fury signifying
nothing. With renewed courage we again approached them^
more cautiously this time,, and soon learned that if we preserved
an extremely composed and dignified demeanor our presence
on the field would be tolerated.

Bemhex, like Philanthus and some species of Sphex, lives in
a sort of semi-social state, a number of individuals occupying
the same space of gi ound, although each one has its separate

AN ISLAND SETTLEMENT. 59-

nest. Bembex, however, differs from these genera and from
almost all of the solitary wasps in her habit of feeding her young
from day to day, or rath.er from hour to hour, as long as it re-
mains in the larval state. This difference in her maternal cares
as compared with those of other species results in a less numer-
ous progeny. The larva, for a period of two weeks, demands
constant attention from the mother, so that a second egg cannot
be laid until the first-born has gone into its cocoon, unless, in-
deed, she feeds two lars^se at once, which does not seem prob-
able. The season of work is ten or twelve weeks so that Wesen-
berg is probably correct in allowing only five or six young ones
to each mother for the summer.*

In watching our wasps Ave found that the new nests w^ere
usually made in the out-skirts of the colony which was thus
continually extending its limits. Like many other species Bemr-
1)CX has great difliculty in deciding just where to dig. Our
Spliex made three beginnings before finally settling down.
The only AmmopJiila that we watched from the beginning
changed her place after working for ten minutes. P. quinque-
notatiis often tried half a dozen places before she was satisfied^
and spinolae is quite as difficult to please.

When, at last, the right place is found, the labor of excavation
is carried on vigorously. The mandibles are used for loosening
the earth and for lifting, but the greater part of the work is
done with the first pair of legs, the tarsi of which are doubled
up while the dirt is swept out with the brush of stiff spiny hairs
on the second joint. This attitude gives them a very comical
aspect, making them look as if they were sweeping with their
elbows. They sometimes lie far over to one side while loosen-
ing the earth with their mandibles. While digging, the body
is held high by the straightening of the third pair of legs and
the dirt comes out behind in a rapid stream, flying to a distance
of three or four inches. Before long the wasp is lest to sight
but every few moments she comes backing out, pusliing behind
her the dirt that she has displaced below. In about fifteen

^Copenhagen Entomologiske Meddelelser, vol. iii., 1891.

60 THE SOLITARY WASPS.

minutes the nest is ready and the wasp turns her attention to
scattering all the dirt that has been thrown out, sweeping the
ground clean so that no sign of her work remains. We have
often speculated as to the meaning of the careful and consci-
entious performance on this part of her task. "With those wasps
that nest bj themselves it is not easy to see what enemy they
are providing against in hiding the entrance to the nest, but the
precaution seems still more unnecessary and even absurd in the
Bembex field, where there is no possibility of conceahng the
colony, and where the nests are only an inch or two apart so
that an enemy might burrow anywhere with the certainty of
finding one. Moreover, the only enemy that we could discover
was the parasitic fly which never attempts to enter when the
hole is closed. However, unmoved by our opinion on the sub-
ject, spinolae spends five or six minutes of her precious time in
making the neighborhood of her home quite tidy, and then she
fills in the mouth of the nest with a little loose earth before
going away to catch her fly.

Oxi/helus, though she is limited in choice by her small size,
can catch a fly in three or four minutes. Bemhex is strong
enough to take anything that she sees, and she has no preference
for one species above another, yet she seldom finds one under
twenty or twenty-five minutes. When she comes back nothing
of the fly is visible unless it is unusually large, so closely is it
held under her bodv by the second pair of legs. She alights
and scratches away the loose earth at the entrance of the nest
with her first legs, and then, as she creeps within, she passes the
fly along from the second to the third pair, so that the end of
its body, projecting beyond the abdomen of the wasp, is visi-
ble for an instant before it is carried inside. Sometimes she
drops the fly behind her and then, turning around, pulls it in
with her mandibles. In other cases, where a longer portion of
the tunnel has been filled with earth, the fly is left lying on the
ground while the wasp clears the way. This offers a favorable
opportunity to parasites, especially as the fly is not placed with
any regard to its safety but is dropped anywhere. The dirt that

AN ISLAND SETTLEMENT. 61

is kicked out sometimes covers it over so that when the way is
clear the careless proprietor must search it out and clean it off
before she can store it away. In one instance, in which we had
been opening a nest close by, the tunnel was entirely blocked
by the loose earth which we had disturbed, and the wasp worked
for ten minutes before she opened a way to her nest. During
part of this time she held the fly, but when she realized that it
was going to be a long piece of work she laid it down near by.
As the wasp enters she sometimes leaves the hole open behind
her, but oftener fills it by pushing up earth from below. When
she comes out again she throws in a little dirt and then begins
to circle about the place. She seems not quite easy about the
nest, however, returning three or four times to scratch earth
over the entrance, before finally taking her departure.

We opened a good many nests in the course of the summer
and found them all very much alike, much more so than is the
case with other species. The entrance tunnel runs in obliquely
for from three to five inches below the surface of the ground, as
is seen in the drawing. (PL XI., fig. 4.)

We grow accustomed to marvels and from our familiarity
with other wasps we take as a matter of course the unerring ac-
curacy with which Bemhex swoops down upon the exact spot
at which the entrance to her nest is hidden. And yet how
strange a power it is! There is not the least sign to help her —
not a stone, not a blade of grass is to be seen on the field. Our
method of marking a nest which we wished to find again was
to place tiny pebbles at exactly equal distances from it, one on
either side, so that the middle point of the straight line between
them gave us the desired spot. By what mysterious insight
does the mother wasp, returning with food for her young, rec-
ognize that undifferentiated spot of ground as the portal of her
home?

We once smoothed over the entrance to a nest, after seeing
the wasp go out, pressing down the earth to make the surface
smooth and compact. When the owner came back she seemed
greatly puzzled, circling about and alighting several times. At

€2 THE SOLITARY WASPS.

last she made up ker mind as to the spot where the entrance had
been and began to loosen the earth with her mandibles. It re-
quired a good deal of digging and sweeping to open up the gal-
lery but she finally succeeded.

A curious thing about these wasps, and one which shows how
much common feeling they have, is that they work in waves,
all starting off on their hunting expeditions within a few min-
utes of each other, and returning together after the chase. At
one time all the residents seem to be present, digging their nests,
carrying in their booty, dashing at each other and chasing the
parasites with a tremendous amount of humming and swoop-
ing about. Then suddenly they are all gone. ]^othing remains
but multitudes of flies which keep up a giddy dance over the
field, and for ten or fifteen minutes the place seems deserted.
Then the wasps begin to return, several coming at a time, and
as if by magic the whole scene awakens to life. More than
half of the wasps bring nothing home with them, and these fall
to robbing their more fortunate companions. Those that are
carrjang flies must pause a moment, burdened as they are, to
scratch away the eai"th at the entrance to the nest. When un-
molested they go in very quickly, but it is just at this point that
the marauders fall upon them, displaying an amount of per-
sistence and energy in their attacks that, were it properly di-
rected, might easily enable them to secure flies for themselves.

We once saw a wasp that had been fortunate enough, or
perhaps unfortunate enough, to catch an immense fly, the wings
•of which stood out on both sides very conspicuously. This
made her an especial mark for her unprincipled relatives. Half
a dozen of them chased her about like chickens pursuing one
of their number that has found a worm. She circled and set-
tled and circled and swooped around for five or six minutes,
continually pursued and attacked by the robbers, and quite un-
■able to get into her nest. At last, curious to see what she was
carrying, we made her drop the fly and secured it for ourselves.
We found it to be Tabamis atratus. It was quite dead but

AN ISLAND SETTLEMENT. 63

showed no marks of violence. It was not wasted for we after-
ward fed it to one ♦ f our wasp nurslings at home.

At another time we saw one wasp attack another that was
bringing in a fly. In the struggle that ensued the owner lost
her booty, as the two rolled over and over on the ground. As
they parted it was seized by the thief. They clinched again
and rolled on the ground as before, and this time the fly was
recovered by the rightful owner. At this point, thinking that
perhaps one of the wasps was a male, and that this might be
their stylo of courtship, we seized both of them, whereupon the
fly was dropped and the two wasps turned their attention to at-
tacking us. Both proved to be females. I^Tot only do the
Bemhecids fight in this way for the possession of their prey,
they even quarrel without any apparent cause. We have seen
two females digging their nests at a little distance apart, one of
which was repeatedly attacked by the other although she did
nothing to provoke the aggressor. They are certainly very un-
neighborly and have no idea of living in harmony. When fly-
ing in a threatening manner, either at us or at each other, they
have a way of wagging their abdomens violently from side to
side in a way well calculated' to inspire teiTor.

In warm sunny weather spinolae works industriously through
the middle of the day and seems detenuined to provide abund-
antly not only for her own offspring but for any unbidden
guests that it may be her fate to care for. She never works
more than four or five hours a day, however, and in unfavorable
weather she does not work at all. On going over to the island
one cloudy morning" to spend some hours in watching the Berti-
bex activities, we found the spot quiet and lifeless. Ko one
seeing it for the first time would have dreamed of the multi-
tudes of living creatures beneath his feet. The nests seemed
to be all closed, but on peering curiously about we found one on
sloping ground, in the suburbs of the colony, of which the door
was open. Just within was the proprietor gazing out on the
landscape, as she is shown in the illustration. (Plate YI.) She
seemed to leaning on her elbows, and her face, enlivened by

64 THE SOLITARY WASPS.

two great goggle eyes, had an irresistibly comical aspect. With,
the exception of the omnipresent flies, this wasp was the only
sign of life about the place. Even in good weather and in
working hours, the wasps sometimes rest, for we have seen
them go in empty handed, closing the door behind them, to
remain for half an hour at a time.

There is one thought that must strike the most casual ob-
server of a colony like this. Why do not these wasps, fly-
catchers as they are by profession, kill the parasitic flies that
infest their homes, thriving abundantly on the fruits of their
labor, a continual menace to the life and safety of their off-
spring? To the uninitiated it would seem that these flies would
serve as food for the wasp larvae quite as well as any of the
dozen species that they actually take, but even if the wasp-mother
believes that they possess indigestible qualities, it would be
much less trouble to kill them and throw them away than to be
perpetually chasing them to a little distance only to see them,
return as soon as she gives her attention to anything else.
Whatever the reason for it may be the relation between the
wasps and the flies is certainly most curious and puzzling.
Fabre's explanation is that since this miserable little fly has its
own part to play in nature, Bemhex must respect it, thus pre-
ser^dng harmony in the world of living things. The idea is
perfectly in accord with his own theories, but we find ourselves
quite unable to accept it.

There can be no doubt that the parasites are a grave danger
to Bemhex. She suffers from them far more than any other
wasp that we are familiar with, her mode of feeding the young
rendering her peculiarly susceptible to their attacks. Of the
ten or twelve nests that we opened only one was free from
them, the others containing from two to five lively maggots
nearly as large as the wasp larvae, which were sharing the food
brought in by the mother. Fabre, who has studied the ques-
tion thoreughly, has found as many as ten parasitic larvae in one
nest. He has also noticed that where the parasites are most
numerous the wasp-larva is proportionately small and emaciat-

AN ISLAND SETTLEMENT. 65

ed, reaching only one-half or one-third of its nornml size.
When it attempts to spin its cocoon it has not strength enough
to do so and thus perishes miserably among the pupae of the in-
terlopers, which have the advantage of developing more rapidly.
He has proved, by experiments upon nests transported to his
study, that although the invaders preserve friendly relations
with the rightful owner of the nest so long as food is abundant,
they nevertheless, at the first suggestion of scarcity, fall upon
the wasp larva and ruthlessly devour it. This "black action"
lie l^as seen with his own eyes. In view of this base ingratitude
we are more than ever impressed with the troubles of the poor
Bemhex mother as she tries to feed a dozen mouths where she
has bargained for only one.

We several times saw a fly follow a wasp into her nest, re-
maining within for half a minute, and it is probable that they
go in to lay their eggs. According to Fabre, it is the habit of
the flies that are parasitic upon the half-dozen species of Bem-
bex that he has studied to seize the moment at which the fly
projects from under the abdomen of the wasp as she enters the
nest, and he has even known them to lay two or three eggs on
one fly in the instant of time that its body was exposed.

When we first found the colony on August tenth, it was
strong in numbers, and it continued to grow up to the first of
September. On going over one day in the middle of August
we found a good deal of work going on, but to our surprise the
flies had disappeared. A careful search showed only two in-
stead of the usual numbers. Their place was taken by dozens
of little wasps, which proved to be Pompilus higuttatus Fabr.
These wa^ps seemed to be merely loafing about amusing them-
selves, neither eating nor working. Whether their presence was
in any way connected ^^viih. the absence of the flies we are un-
able to say but it seems probable that they had congregated on
the Bemheoo gTound merely because it was an open spot, since
on looking about we found them covering every open sunny
space that the island afforded.

Fabre took a partly grown Bemhex larva from the nest, where
5

66 THE SOLITARY WASPS.

it was surrounded by tlie remains of twenty flies. He fed it
generously and it ate sixty-two more, making a total of eighty-
two in tlie eight days that passed before the spinning of the
cocoon. Our experiments in this line gave similar results. We
took charge of a partly gTOwn larva on the afternoon of August
tenth and between that date and August fifteenth, when it spun
its cocoon, it ate forty-two house flies besides a big Tabanus.

Fabre thinks that under natural conditions the mother does
not give the larva all it can eat at one time but provides it with
what she considers a reasonable amount of food, and keeps any-
thing that she catches beyond this out of its reach. He draws
his conclusion from the fact that he has found several flies in
the tunnel leading to the nest, while the larva had as many
more close to it. It would certainly be convenient for Bemhex
to have a reserve of this kind in case of rainy weather, but
the forethought required for such an action seems to require a
higher degree of intelligence than can be claimed for her.

In one nest we found a single fly with a long cylindrical egg
attached to the left side of the thorax just at the origin of the
third leg. In another, which we had seen made and provis-
ioned, we found, six days later, a larva which we judged to be
four days old. Assumina; that the e^g was laid on the first day
it must have taken it about two days to hatch. Other nests
gave us larvse in all stages of development, surrounded by the
remains of diptera, among which Syrplius, Tabanus, and Musca
were represented.

In regard to the condition of the flies captured by Bemhex
we have never seen the crushing of the thorax, which is noted
by both Wesenberg and Fabre. Indeed the flies that we found
were not always dead, since in two instances they responded
readily to stimulation. Similar results have been obtained by
Mr. S. W. Dunning of Hartford, Connecticut, whose note on
the subject is as follows:

"One female observed around burrow. Burrow ran at an angle of
40° from surface, was 4-5 inches deep and contained one larva and a
number of partially destroyed and some* whole diptera. Those that

AN ISLAND SETTLEMENT. 67

were whole quivered the legs on provocation. Larva was 1-3 of an
inch long. The flies consisted of one small Asilid, one Syrphus, and
one Blue-bottle, with three or four other partially destroyed and
smaller species."

Twice we have seen our spinolae, as she was bringing liome
her prey, alight near the nest and sting it as it was held with
the second pair of legs. We conld see the process distinctly since
she is slow and clumsy, and, in one instance, had difficulty in
reaching the fly, falling over to one side in an awkward manner.
It is probable, then, that this is a habit with the wasp, but that
the sting is usually given at the place of capture.

Fabre explains the habits of Beinbex in regard to feeding her
young by the nature of her prey. Diptera must be seized while
in rapid motion — therefore they are likely to be crushed and
killed as there is no time for nicety of handling. They contain,
relatively, but a small amount of moisture — therefore they can-
not resist desiccation and would become unfit for food if they
were stored up in numbers to last through the period of larval
life.

This seems reasonable, although we know that Benibex can,
since she often does, catch her flies so delicately that not a hair
is injured. As to the rapidity of desiccation, this would
scarcely hold true, for the crickets used by Lyroda in feeding
her young from day to day, and at any rate, some of the big,
soft-bodied flies that are taken by Bembex are quite as juicy as
the Gastera^anthidae, beloved oiPelopaeus fistularis,'^ or as
some of the beetles taken by Cerceris. Be that as it may, ws
have another suggestion to offer.

May it not be that instead of having departed from the or-
dinary habits of the solitary wasps, Bemhex, in its relations to
the larva, represents the original or least modified form of all
the wasps? In their semi-social habits the wasps of this genus
seem to show a stage in the transition from the earlier state of
the truly solitary species toward the more complex and higher
relations existing among those that live in communities. The

*Bates, Naturalist on the Amazon, p. 186.

68 THE SOLITARY WASPS.

Bemhecids cannot strictly be called solitary, and yet the extent
of tkeir cooperation seems to be limited to the act of driving
intruders away from tkeir nesting-grounds. Beyond this they
have no common cares nor duties.

As to their relation to the laiTa, however, there seems to be
nothing transitional. Compared with the solitary wasps they
are at a great disadvantage, both as regards the burden of feed-
ing the young and the consequent low rate of increase, and in
their constant expo:ure to the attacks of parasites; and they are
very evidently in a less developed stage than the social wasps,
where all the workers join together in the labor of feeding the
young.

It may be possible, then, that all wasps originally fed their
larvse from day to day as Beiiibex now does, and that while the
instinct of paralyzing the prey and of storing the whole supply
of food once for all was working itself out among the solitary
wasps, the instincts connected wdth life in a true society, and of
joining together in the work of feeding the larvse, have, on the
other hand, developed into those of our wasp communities.

If we look at the matter from this point of view we find
among the Ammophilae an instance which looks like a connect-
ing link between the habits of Bemhex and those of the solitary
species. A. iirnaria stores one caterpillar, lays an egg on it,
catches another and stores it as soon as she can and then closes
the nest. As a usual thing, no doubt, the nest is finally closed
before the egg is hatched, so that she never sees her larva. In
one of our instances, however, the capture of the second cater-
pillar was so much delayed that when it was brought in the
mother-wasp found a larva of a day old feasting on the one al-
ready provided.*

We opened a number of the nests of spinolae but only suc-
ceeded in raising one of" the larvse. Our notes on the subject
are as follows:

*Something like this was suggested by Prof. Duncau in 1872 (See
Eomanes', "Mental Evolution in Animals," p. 191).

AN ISLAND SETTLEMENT, 69

No. 44. August 10, 3 P. M. Opened nest and found a half grown
wasp larva and five larvae of parasitic flies, all eating. The fly larvae
were very lively and were two-thirds as large as the other. They
were surrounded by the remains of large numbers of flies. We gave
the wasp larva seven house-flies.

August 11, S A. M. The larva has eaten all the flies put in yester-
day. We now give it six house-flies and the large Tahanus taken at
the colony.

August 12, 5 P. M. The flies are all eaten. The larva is very large.
We now give it ten house-flies.

August 13, 9 A. M. The flies are not quite gone but we give it eight
more,

August 14. The larva has eaten all the flies. We give it six more.

August 15, 8 A, M. We give the larva eight flies. — 5 P. M. The
larva has left three flies uneaten and has begun to spin its cocoon.
In five days it has eaten forty-two flies besides the big Tahanus,

No. 46. August 10. We saw spinolae take a fly into the nest. After
a short time we opened the nest and found the fly vnth. an egg attached
to the left side of the thorax just at the base of the third leg. It was
long and cylindrical. The fly belonged to the genus SyrpJius.

August 13. The egg is evidently dead.

No. 54. We opened a nest and found a larva two-thirds grown,
three active maggots, and the remains of flies.

No. 55. On August 10, 3:45 P. M. We saw a nest made and a fly
taken in- We opened it today, August 16. Assuming that the egg
was laid on the first day, we judge that it hatched in two days, since
the larva seemed to be about four days old. We found no maggot in
this nest, and not many remains of flies.

Mr. Hudson gives an account of a common La Plata species
of tids family that has the same habits.* This wasp, Monedula
jnmctata, digs her hole and lays therein a single egg. "When
the grub hatches the parent keeps it bountifully supplied with
insects since it is sometimes surrounded by an accumulation of
six or seven which are still untouched. The prey taken con-
sists to some extent of fire-flies and other insects, but flies are
always preferred. The nest is always closed by the wasp be*
fore she leaves it, to protect it, Mr. Hudson thinks, from hunt-
ing-spiders, ants, and tiger-beetles. No mention is made of

*Naturalist in La Plata, p. 162.

70 THE SOLITARY WASPS.

parasitic flies. Can it be tliat tliere is one spot in the world
where the wasp is free from them?

Probably Moncdnla, like Benibex, lives in colonies^ since it
is said that as a nsnal thing many of their holes are found close
together. It occasionally captures insects on the wing but
more frequently pounces down on them when they are at rest.

This species, then, differs from Beinbex spinolae in its cap-
ture of other insects, besides flies, and in its habits of lajang the
egg in the empty nest, no food being brought until the grub
is hatched. ■ In both respects the southern species seems to have
made an advance upon the intelligence of our Bemhecidae.

Another interesting variation is that of Benibex ciliata ob-
served by Mr. Bates in Santarem.* This wasp excavates her
gallery and then goes off to catch her fly, leaving the door open.
This sometimes happens vdth spinolae, but never with the
European species rostrata, and, as we have seen, Monedula also
carefully closes the door before leaving it. Ciliata,to be sure,
does all that is necessary, since after the fly has been taken in
and the egg laid, the doorway is filled up. Ciliata, as well as
spinolae, circles about and takes her bearings carefully before
leaving the spot.

Mr. Bates has also some notes on Monedula slgimta, which
differs to a remarkable degree from punctata since it not only
taken nothing but flies, but even confines itself to a single
species, although it must sometimes go half a mile away to find
it. This reminds us of Pompilus quinquenotatus w^hich never
takes anything but Epeira strix.

A considerable contribution to our knowledge of the genus
Bemhex has been made in the paper by Wesenberg (written in
Danish) which has already been referred to. This paper deals
with Benibex rostrata. • It was translated for Mr. Ashmead by
Mr. Martin Linell.f The account is most interesting.

It seems that rostrata makes its nest in solid sand, covering

*Naturalist on the Amazon, p. 181.

tAculeate Hymenoptera, III., Psyche, vol. 7, no. 216, p. 62.

AN ISLAND SETTLEMENT. 71

it up witli loose sand and usually, also, with a little flat stone,
to prevent parasites from entering. The cell measures one
cubic inch, the entrance tunnel being one and one-half centime-
ters long, and arcuate. A cell contains four or fiA^e fresh flies
(Lucilia, Eristalis, etc.), and torn off wings, sucked out thor-
aces, and in the middle of these, a big flat larva.

When the larva is hatched the mother brings more and
more flies, the flies being larger and larger as it grows. This
adjustment of the size of the fly to the growth of the larva has
also been noted by Fabre.

Wesenberg says that flfty Bemhecids will nest on a spot as
big as a room during a period of three months. The time re-
quired for the development of the larva is two weeks, this
giving five or six young ones for the season. He queries,
"Does each female have more than one nest? and if so how can
she remember them?" To determine this point we marked six
wasps by touching them with differently colored paints, putting
near their nests pebbles painted to correspond with the owners,
and then watched them closely for three hours. During this
time the red wasp returned regularly to the red nest, the blue
to the blue, and so on. They were watched for an hour and a
half on the following day with the same result. So that it
seems quite certain that spinolae has only one nest at a time.
To feed two larvae at once, with interlopers thrown in, would
be a heavier task than the most determined industry could ac-
complish.

Wesenberg states that all the digger-wasps with the exception
of Bewibeos furnish the food for their young once for all, either
first laying the egg and then putting in food, or first filling the
cell with food and then laying the) egg upon it, and covering the
whole without again visiting the cell or seeing their larva. We
know now that this too general a statement. At least one spe-
cies of Lyroda (siiMta) brings food to its young from day to
day. We have seen that Monediila does the same. In West-
wood's "Classification" we find that the same habit has been

72 THE SOLITARY WASPS.

claimed for Mellhms by Mr. Curtis (p. 175); for Pelopaeiis by
Bonnet (p. 206); and for Sphex by Mr. Bartram (p. 207).
These statements, and also tbose pertaining to Bemhex, were dis-
believed by Westwood wbo tbougbt that only social wasps re-
visited the nest after the egg had been laid. Certainly Sphex
and Pelopaeiis have entirely different habits. Of MeUinus we
have no knowledge.

THE LITTLE FL YCA TCHER. 73

CHAPTEE YII.

THE LITTLE FLYCATCHER.

Oxybelus quadrinotatus Say.

Plates YIIL, fig. 7; XIII., fig. 3.

In studying the species tliat come in our way we are contin-
ually developing unaccountable likings for some kinds above
others. The appearance of one of these favorites is always
hailed with delight, and when the season's work is over we re-
member them with lively pleasure.

It is thus, dear little Oxyhehis, that we dwell upon the thought
of you and your pretty ways. JSTo other wasp rose so early in
the morning, no other was so quick and tidy about her work,
so apt and business-like without any fuss or flurry. No other
was more rapid and vigorous in pursuit of her prey, and we
think with admiration and gratitude of the number of flies that
you must have destroyed in the course of the summer.

0. qtiadrvnotahis is only one-quarter of an inch long and is
dark gTay with four whitish spots on the abdomen. It was be-
fore nine o'clock in the morning that, while out on an early in-
spection tour in the garden, we saw our only example of this
species descend upon a sandy spot and after a moment's rapid
scratching with her first legs, enter the hole that she had
opened.* Under her body she was carrying a fly which looked
like the common domestic species. It was upside down, its
head being tightly clasped with the third pair of legs, and all
of its abdomen projected beyond the abdomen of the wasp.
Ashmead quotes from Pabre the remarkable statement that
Oxyhehis carries her flies home impaled on her sting. This

*During the following summer this species became so common that
we studied many examples.

74 THE SOLITARY WASPS.

idea, probably arose from the fact that nearly the whole body of
the fly is visible.

Our new found wasp stayed only a moment in her nest, al-
though, as we afterward found, it was long enough for her to
lay her egg on the fly. When she came out she quickly
smoothed the sand over the spot with her head and legs so that
there was notliing to mark the nest, and flew away. In three
minutes she returned with another fly. She alighted two or
three inches away and scratched for an instant, but quickly saw
her mistake and found the right spot.

Again and again the pretty little worker went and came,
wliile we sat watching close by, admiring her deft handiwork in
opening and closing the nest and wondering at the ease with
which she found it at each return. There was nothing tire-
some or dilatory about this species. Within twenty minutes
we had seen six flies stored up. The nest was closed and the
place smoothed over every time before she went away, but when
she entered she left the door open behind her. We once tried
to make her drop the fly, but when disturbed she flew up and
alighted on a plant near by, keeping her hold on it. The whole
performance was brisk and business-like but without the fever-
ish hurry of Amiiiophila and Pompilus.

After the sixth fly Avas taken in we were afraid to let her go
again for fear that the nest was now completely provisioned,
and that she would not return. She was such a charming Httle
wasp, scarcely bigger than ai fly herself, and yet so useful in her
industry, that we hated to disturb her, but as we were obliged
to have her for identification we first caught her and then
opened the nest. (PI. VIIL, fig. T.) It contained only the
flies that we had seen taken in, the egg being attached to the
one lowest down on the left side, between the head and the
thorax. It was long and cylindrical. The flies were dead but
showed no marks of violence.

She must have dug the nest before catching the first fly, as
there was no delay when she brought it in; and if, as seems

THE LITTLE FL YCA TCHER. 75

probable, the work was done tliat morning; the task must have
been begun at a very early hour.

The egg, which was laid just before nine o'clock on the morn-
ing of August seventh, hatched at a little after nine on the
morning of August eighth. The larva began to eat at once and
devoured all the inside of the thorax and abdomen of the fly
to which it was attached, in the first twenty-four hours. On
August twelfth it had reached the sixth fly, and we supplied it
with three more. On August fourteenth these were gone and
we again replenished its larder, this time with two flies. The
larva had partly eaten these when something went wrong. Its
appetite failed, and on August sixteenth it died.

We find but meagre notes on the genus Oxijhelus. Ashmead
says that no observations have been made on the American
species but that in Europe they are found to burrow in sand
and to provision their nests with dipterous insects. He also
says that according to Verhoeff the species in this genus do not
paralyze their prey by stinging as they are unable to do so on
account of the rigidity of the abdomen, but that instead, they
crush the thorax with the mandibles just beneath the wings,
the centre of the nervous ganglia. He found in one nest a
dozen flies (Hydrotaca) and all had the thorax crushed and
were dead. In the case of our wasp we do not know how the
flies were killed but there was no crushing of the thorax. The
larva devoured, in all, ten flies. At the time of its death it had
probably finished the lai-^^al stage of its existence since nine
days had elapsed since the hatching of the egg. It may be that
this period just before pupation is a critical point in the life
history of a wasp. We lost several of our nurslings at this time,
and Fabre has noted that when, on account of the presence of
parasites, the lar\^a of Bembex rostrata had lacked something
of its usual amount of nourishment, it perished miserably at the
end of its larval stage, not having strength enough to spin its
cocoon. No waspling in our charge ever died from lack of nour-
ishment — on that score our consciences are clear; but it was

76 THE SOLITARY WASPS.

sometimes difficult to make their conditions quite normal, and]
for this reason we may have been, indirectly, the cause of their
death.

The way in which our Oxyhelus carries its prey is peculiar to
itself. Bembex and PMlantJms also hold their prey under the
body but use the second pair of legs, so that it does not project
behind except at the moment of entrance into the nest. Qucbd-
rinotattis, as we could distinctly see, since she passed close to
us several times in quick succesison, clasps the head of her vic-
tim in the third pair of legs, and flying thus, with its whole body
sticking out behind her, she certainly presents a very remark-
able appearance.

THE WOOD-BOBEES. 11

CHAPTER YIII.

THE WOOD-BORERS.

Trypoxylon albopilosum Fox and Trypoxylon riibrocinctum

Packard.

Plate XIV., fig. 1.

In the autumn of 1895 we publislied some notes on these two
species.* Since that time we have given a good deal of atten-
tion to these wasps and have gathered some new facts as to
their habits, and we have therefore thought it best to rewrite
their life history, including such portions of our former paper
as would serve our purpose. They are both slender-waisted black
wasps, albopilosum having bunches of snowy white hairs on
the first legs, and measuring three-quarters of an inch in length,
while ruh^ocinctum is a little smaller, and, as the name implies,
wears a red girdle.

Although these wasps are called wood-borers they will use
convenient cavities in any material. When we went out to our
summer cottage, in the last days of June, 1895, we found many
little wasps of the species Trypoxylon riihrocinctum busily work-
ing about a brick smoke-house on the place. Closer examina-
tion showed that in the mortar between the bricks were many
little openings leading back for a considerable distance, which
were occupied by the wasps. It would seem that these holes
were excavated by some other agency than the wasps themselves
as they were so much too deep for their purposes that before
using them they built a mud partition across the opening about
an inch from the outside of the wall. Later on we found nests
■of the same species in the posts which support an upper balcony

♦Psyche, Nov., 1895, pp. 303-306.

78 THE SOLITARY WASPS.

of tlie cottage, and here, too, tlie wasps made use of lioles which
were already excavated.

In the following summer we found large numbers of these
wasps at work in a straw-stack. The stack had been cut off
perfectly smooth on one side so that many thousands of the cut
ends of the straws were exposed to view, and these proved very
attractive to rtihrocinctiim. This species is very cosmopolitan
in its tastes, for we also found it utilizing the small holes in the
sticks of a w^ood-pile. The straws made the dainties': nesting-
places, however, and were well adapted to our purposes since
they could be drawn out of the stack and split lengthwise so
that the contents could be easily studied. The two halves could
then be brought together again without injuring the inhabi-
tants, and thus we often kept several sets under observation long
enough to watch the changes from the egg to the pupa. We
found Trypoxylon alhopilosum nesting in holes made by beetles
in posts and trees, but never in straws. A third species, biden-
tatum, was very common, nesting in the stems of plants. Dur-
ing the month of August we saw many individuals of this spe-
cies hunting for spiders on the blackberry bushes, but at this
time we were so much absorbed in Crahro stirpicola that we
never followed them to their homes.

Rubrocinctum was more conveniently studied, and through
July and August we watched the comings and goings of these
little wasps. They were very good-tempered, never resenting
our close proximity nor our interference "v\4th their house-keep-
ing. By working hard they could prepare a nest, store it with
spiders and seal it up all in the same day. This we have seen
them do in several instances. In other cases the same operation
takes three or four days. In the second summer that we worked
with them we found one very energetic mother that stored four
nests in one day. It had rained hard on the twenty-sixth of
July and no wasp works in such weather. On the afternoon of
the twenty-seventh we took a straw just as the little mother was
bringing in a spider. "We opened it and found that the inner-
most cell contained eight Epeirids, with an egg on the abdomen

THE WOOD-BOHERS. 79

of the last one taken in ; the second cell was provisioned with ten
spiders wdth the egg on the seventh, so that three had been
brought in after it was laid ; the third cell had the egg on the
last spider, as did also the fourth. All of these eggs hatched
on the twenty-ninth, the two outer ones, that were laid last, be-
tween eight and nine o'clock in th'e morning and the two that
were laid earlier between two and three in the afternoon. This
was the biggest day's work that we have ever recorded for any
of our hunting wasps.

With both species (T. ruhrocinctmn and T. alhopilosum),
when the preliminary Avork of clearing the nest and erecting
the inner partition has been performed by the female, the male
takes up his station inside the cell, facing outward, his little head
just filling the opening. Here he stands on guard for the greater
part of the time until the nest is provisioned and sealed up,
occasionally varying the monotony of his task by a short flight.
As a usual thing all the work is performed by the female, who
applies herself to her duties with greater or with less industry
according to her indi^adual character; but the male doubtless
discharges an important office in protecting the nest from para-
sites. We have frequently seen him drive away the brilliant
gi'een Chrysis fly which is always waiting about for a chance to
enter an unguarded nest. On these occasions the defense is car-
ried on with great vigor, the fly being pursued for some distance
into the air. There are usually two or three unmated males fly-
ing about in the neighborhood of the nests, poking their heads
into unused holes, and occasionally trying to enter one that is
occupied, but never so far as we have seen, with any success,
the male in charge being always quite ready and able to take
care of his rights. The males, however, made no objection
when strange females entered the nest as they sometimes did by
mistake, nor did the females object to the entrance of a strange
male when the one belonging to the nest happened to be away,
but in such cases the rightful owner, on his return, quickly
ejected the intruder. We often amused ourselves, while we were
watching the nests, by approaching the little male, as he stood

80 THE SOLITARY WASPS.

in his doorway, with a blade of grass. He always attacked it
valiantly, and sometimes grasped it so tightly in his mandibles
that he could be drawoi out of the nest with it.

When the female returns to the nest with a spider the male
flies out to make way for her, and then as she goes in he alights
on her back and enters with her. When she comes out again
she brings him with her, but he at once re-enters, and then,
after a moment, comes out and backs in, so that he faces out-
ward as before.

In one instance, with ruhrocinctum, where the work of stor-
ing the nest had been delayed by rainy weather, we saw the male
assisting by taking the spiders from the female as she brought
them and packing them into the nest, leaving her free to hunt
for more. This was an especially attentive little fellow, as he
guarded the nest almost continuously for four days, the female
sometimes being gone for hours at a time. On the last day he
even revisited the nest three or four times after it had been
sealed up.

It is upon the female that the heaviest part of the work de-
volves. As soon as she has put the nest in order she begins the
arduous task of catching spiders wherewith to store it. It usu-
ally takes them from ten to twenty minutes to find a spider and
bring it home, but they are sometimes absent for a much longer
time. When the spider has been can*ied to the nest the process
of packing it in begins. This occupies some time and, appar-
ently, a good deal of strength, the female pushing it into place
with her head with a total disregard of its comfort, all the spi-
ders that are caught being pressed and jammed together into a
compact mass. While she is busied in this way she makes a loud,
cheerful humming noise. The number of spiders brought seems
to depend upon their size, in which quality they vary greatly,
the largest ones being six or eight times as large as the smallest.
Ruhrocinctum fills her nest with from seven to fourteen, wliile
the larger albopilosum brings as many as twenty-five or thirty.
Those that we examined represented many different genera, and
even different families, although they were usually Epeiridae.

THE WOOD-BORERS. 81

In a number of cases, during tlie first summer, after several
spiders had been stored, we gently drew tbem out with a bent
wire. In one nest in wluch there were five spiders, we found,
two hours after they had been stored, that three were alive and
two were dead. In another, which the wasp had just begun to
seal up, were ten spiders. Three of these were injured in being
drawn out. Of the remainder four were alive and three dead.
On the anterior part of the dorsum of one of the living spiders
was the egg. It had probably been fertilized as the female car-
ried the male into the nest on her back.

When we discovered ruhrocmctum in the straw-stack we
made many observations as to the position of the egg and the
number and condition of the spiders. We found that the egg
was always placed either on the side or the back of the anterior
part of the abdomen. The number of spiders stored was, as we
have already stated, from seven to fourteen. A fact that in-
terested us greatly was the remarkable accuracy shown by the
wasp in never selecting too large a spider for the calibre of the
straw. Oftentimes it was an extremely close fit, but it could
always be squeezed down. When they nested in posts they
used at times much larger prey. Unfortunately we never saw
this species capture its prey, nor could we prevail upon it to
sting in captivity, but the number of spiders that we found in
straws was so large as to afford abundant evidence concerning
the degree of surgical skill possessed by the wasps. Most of the
spiders taken by ruhrocinctum are inoffensive creatures and
there is no need to be careful or adroit in dealing with them.

The concentration of the nervous system in the Aracknida
would seem to conduce very strongly to uniform results from
the stinging of the wasps. Unlike the larva used by Ammo-
phila, with its chain of ganglia, in the Araneidae the whole cen-
tral nervous system, including the brain and the ventral cord,
forms a single mass, pierced by the oesophagus. The greater
part of this mass^ which lies behind the oesophagus, represents
the fused ventral cord from which the nerves radiate. The
drawing (PI. VIII., fig. 8), gives a clear idea of this nervous
6

82 THE SOLITARY WASPS.

aggregation, and skows bow little difficulty would be encountered
by tbe sting of tbe wasp in entering it. It is evident tbat a
tbrust given in almost any part of tbe ventral face of tbe cepbalo-
tborax, or even on eitber side of tbe anterior balf of its edges,
would reacb tbe nervous center. Witb tbese facts before us
let us turn to tbe notes made upon tbe condition of tbe spiders
tbat bad been stung and stored up in tbe nests of tbe straw-
stack. By tbe "first cell" we mean tbe last one stored, wbicb
wa$ naturally tbe first one opened.

July 11. Opened a nest of i-ubrocinctum. The first cell contained
fourteen live spiders with a newly laid egg. Some of the spiders were
very lively, moving spontaneously. Second cell, ten spiders, one dead,
others alive, and an egg. Third cell, eight spiders, three dead and five
alive, and the egg.

July 12. In each of the first and second cells one spider has died
since yesterday, while in the third there is no change in their condi-
tion. The egg in the third cell hatched at nine in the morning, and
the one in the second cell at three in the afternoon.

July 13. In the first cell all the spiders are dead but one, and in the
second, all but four, while in the third none are alive.

July 15. All the spiders in the second cell are dead.

July 16. The one spider in the first cell has outlived all the others,
but that, too, died today.

Tbe record of anotber set of nests is as follows: On July
eigbtb we took a straw witb a wasp as sbe went in mtb ber spi-
der. Tbe cell was not sealed up. It contained fourteen speci-
mens of tbree species of Epeirids, and tbe egg was, apparently,
just laid. Tbe spiders were pusbed in very tigbtly and tbe legs
and abdomens were, in many cases, bent to one side. All were
limp, but alive. By July tentb, four were dead; on July
eleventb tbe egg batcbed. By July tbirteentb all of tbe spiders
were dead.

It is unnecessary to give tbe bistoiy of otber nests in detail,
since tbese facts make it clear tbat tbere is a great variation in
tbe degree of severity witb wbicb tbe spiders are stung, so tbat
wbile witb some tbe paralysis is complete, witb otbers it is only
partial. Some were killed outrigbt, others lived two or tbree

THE WOOD-BOREBS.

83

days, while still others survived for two weeks. Compared with,
the work of the Pelopaei it would seem that a smaller number
of the spiders are killed at once, while a larger number die after
the lapse of a few days. jSTone of the victims of Trypoxylon
live so long as the most perfectly paralyzed spiders of the mud-
daubers. The two longest lived spiders of Trypoxylon lived
ten and fifteen days respectively, while with Pelopaeus one sur-
vived until the thirty-eighth and one until the fortieth day.

The accompanying table shows the number of days that the
Trypoxyloii spiders lived after having been captured and oper-
ated upon. "We wish to avoid any suggestion that would imply
a lack of skill on the part of the wasps, from the fact that they
killed rather than paralyzed their victims. Possibly the best
criterion of their success is the rapidity with which the spiders
are captured and stored, irrespective of their condition. Dead
spiders seem to be quite as wholesome for their nurslings as
living ones.

Table No, I. — Shoiving length of life of spiders found in nests of

T. ruhrocinctum.

No.

of

nest.

Condition
of spider

when
found.

Number of day t that the spider lii
after the nest was opened.

ed

Remarks.

Dead

Alive

1

2

3

4

5

6

10

15

1

9
5

"i"

3

"z"

4

4

2
12
14

9
6
10
7
5

3

"2"

1

Larva two days old.

2

Larva one day old.

3

"i"

2
1

4
5
8
3
1

33

5

5

Egff just laid.

4

1

Egg one day old .

5

4

Effg one day old.

6

Egg nearly two days old

7

2

Egg on abdomen of spider.

8

3
12

1
1

3

"i"

1

Egg one day old.

9

2
10

3

Egg just laid.

1

5

Total

24

68

The egg requires from forty to sixty hours for its develop-
ment and the larva feeds for seven or eight days before spinning
its cocoon. Those that we watched, usually first disposed of the
abdomen and then of the cephalothorax; sometimes they would

84 THE SOLITARY WASPS.

consume several abdomens before attacking tlie otber parts.
After the body was devoured tbe legs were picked up and eaten.
"When the supply of food was generous, portions of the spiders
were sometimes left untouched. The cocoons resembled in gen-
eral appearance and structure those of Pelopaeus.

"When a female returns with her load she usually hunts about
for a few moments before finding her nest, sometimes entering,
first, two or three that are empty or are occupied by other wasps,
but we do not wish to cast any reflection upon the sense of lo-
cality of a creature that is able to find one particular straw out
of the many thousand? in an expanse of stack twenty feet high,
by twelve wide. We ourselves can testify, from experience, to
the extreme difficulty of the task.

After the storing process is completed the female seals up the
nest with mud. In the case of one ruhrocinctum that we were
watching she began to close the opening at four in the afternoon
and finished her work just thirty minutes later. In this time
she made ten journeys for mud, bringing it in pellets in her
mandibles. In another case, also a ruhrocinctum, the female,
after bringing so many spiders that the ceE. was full up to the
very door (which we, saw in no other case), went away without
closing it and never returned. The male seemed uneasy at her
conduct and several times flew away, staying an hour or two
and then returning; but after a time he too deserted the nest.
Whether some evil fate overtook the female or whether there
was some failure of instinct on her part can only be conjectured,
but the latter hypothesis is not untenable, since out of seventy-
six nests that we had under observation seven were cleaned out
and prepared and were then sealed up empty. We have often
found similar oases among the nests of the blue mud-dauber
wasps, where it is not a very uncommon thing for the absent-
minded females to build their pretty little cylindrical nests with
infinite care and patience and then to seal them up without put-
ting anything inside. '

Cocoons of ruhroemctum that were gathered in the month of
August remained over the winter and hatched in May and June.

THE WOOD-BOREBS. 85

Almost as interesting as rubroeinctum is the slightly larger
species, T. albopilosiim. This wasp has a great liking for the
posts that support the balcony of our cottage, a preference that
is very convenient for us, as it enables us to sit in the shade and
watch their doings at our ease.

One afternoon as we sat, literally, at our posts, a female of
albopilosum came humming along, looking very important and
energetic, as though she had planned beforehand exactly what
to do. She entered an empty hole, head first, and at once began
to gnaw at the wood, kicking it out backwards with considerable
violence. After a few minutes she changed her method of
work, and began to caiTy out loads of wood dust in her mandi-
bles, dropping it in little showers just outside the nest, and then
hastening back. In forty minutes she carried out, in this way,
upwards of fifty loads. She then flew away, but returned in
ten minutes with a male. She alighted, he took his place on
her back and they went in together.

After a time they came out and both flew away, but the next
morning they came back and the nest was stored.

In this species the male does not always come out of the nest
when the female brings a spider. Perhaps the nest is enough
larger than in ruhrocinctum to accommodate them both com-
fortably. As a usual thing, however, he enters on the back of
the female. The spiders brought by albopilosum are larger than
those used by rnhrocinctum. They sometimes bring such heavy
specimens of Epeira insiilaris that they are carried with diffi-
culty, the wasp alighting and dragging the spider into the hole
instead of flying directly in as usual.

"We watched a number of albopilosum nests during the sec-
ond summer, finding them in several instances through the loud
humming of the female while she was pushing the spiders into
her hole. From our not very extensive study of the spiders
taken by this species we are of the opinion that some are killed
at the moment of capture, and that those that are only paral-
yzed die in the nest from day to day.

Mr. W. H. Ashmead has noted that albopilosum stores its nest

86 THE SOLITARY WASPS.

■with, aphides, but in the cases that we observed they used
only spiders. There can be no mistake on this point as we more
than once took the spider from the wasp as she was entering the
nest. In a recent letter Mr. Ashmead says that his notes were
made in the field, and that he probably mistook some closely
allied species for this one.

We sometimes found the parasitic 3l€littoMa fly in the nests
of ruhrocinctum, and from two nests we reared the common fly
Pachyophthalmns anrifrons.

We do not know how many nests are stored by the female in
one season, in any of the species of Trypoxylon.

We are not as familiar with the habits of T. hideiitatum as
with those of the other two, but we have a few notes relating
to the female. This little worker is the smallest of the three,
and like her sisters is a confirmed spider hunter. Once, when
out among the raspberry bushes, we had the good fortune to
witness a capture. The wasp seized the spider as it rested on a
leaf, by the top of the cephalothorax and, holding it firmly,
cuiwed her abdomen under and stabbed the under face of the
cephalothorax. All her motions were deliberate, and after the
operation she delayed a moment before picking it up by a leg
and flying off. We often found raspberry stems which had
been filled with spiders by this wasp, but we do not know the
length of time required for the development of the egg nor how
long the larva eats before pupation. The cocoon is very dif-
ferent in appearance from those of ruhrocinctum and alhopilo-
sum, being excedingly long, slender, and almost white, instead
of short, wide, and brown. The perfect insects come out in
September and the last cocoon formed is the first one to hatch.
This was also true of the cocoons of ruhrocinctum formed in
straws. The different habits of the hymenoptera in this respect
are very interesting. In the case of Ceratina ditpla, the small
carpenter bee, the egg first laid hatches first, those above fol-
lowing in regular order. The lower ones wait patiently in their
cells until the one in the top cell has matured, when they all
come out at once. This is a very common species with us. Mr.

THE WOOD-BORERS. 87

Comstock says that, so far as lie knows, dupla is the only solitary
bee that watches over her young until they become mature. In
the case of some of the cuckoo-flies (Chrysididae), we have ob-
served that the egg laid first hatches first, but that the mature
insect, instead of waiting for the way to be clear, gnaws a hole
through the side of the stem, and thus makes its entrance into
the world.

Years ago, when we found that many of the Epeiridae laid
enormous numbers of eggs (A. cophinaria from 500 to 2000),
we wondered what became of the thousands of spiderlings. An
acquaintance with Trypoxylon has shown us their fate, and has
given us an illustration of how closely the two groups are re-
lated. To make a very modest estimate there must have been
twenty wasps at work in our straw-stack. During the six weeks
which make the busiest part of their working season each of
these must have stored, at the very least, tliirty cells, putting an
average of ten spiders into a cell. It may then be considered
certain that the straw-stack, with its working surface of 12x20
ft., was the mausoleum of six thousand spiders, and it is very
probable that twice as many were interred within its depths. It
must be remembered, too, that before the spiders have grown
large enough to be interesting to ruhj'ociiictum, hidentatiimlnas
had her turn at them, and that those that are allowed to grow
too large for rubrocinctmn, are preyed upon gi-ade after grade,
first by alhopilosttm and finally by Pelopaeus, Pompilus, and
other genera.

The wasps of this genus lose their interest in family affairs
after the second week in Aiigiist, though after this time they
may still be seen taking their well-earned holiday on the blos-
soms of the aster and the golden-rod.

88 THE SOLITARY WASPS.

CHAPTER IX. /'

THE BUG-HUNTERS. '

Astata unicolor Say.
Plates IX., fig. 5; XI., fig. 3; XII., fig. 4.

This species varies mucli in size, the larger ones being about
half an inch long. It is black, the thorax having some white
pubescence while the abdomen is smooth and shining.

We had so often followed these wasps without seeing them
capture anything that we had almost come to beheve that they
were chasing a will-o'-the-wisp, or something equally intangible.
For a long time we could get no clue to their lives but at last
a day came when we saw one drop into a hole in the gi'ound
which showed a good sized opening with earth heaped all
around, more on one side than on the other. Within six inches
was a second nest, mo:'e perfectly shaped, with a funnel-like
opening exactly like that of Cerceris clypeata, and this was oc-
cupied by a second wasp of the same species. They were both
busy carrying in nymphs of Podisus modestiis Fabr., which
they held by the base of the antennae, venter up, grasping them
with the mandibles and supporting them, more or less, while
flying, with the second pair of legs. Every time that a bug was
brought home the wasp ahghted and walked around near the
nest for a few minutes, and then went in head first. One of
them paid no attention to us but the other chowed much annoy-
ance at our presence and buzzed about for some time before go-
ing in. Before taking their departure they almost invariably
made a long locality study, first running about on the ground,
flirting their wings nervously as they went, and then rising
and circling all around the place. (PI. XII., fig. 4.) Their
periods of work evidently alternated with spells of idleness for

THE BUG-nUNTEES. 89

after bringing in three or four bugs they would disappear and
nothing would be seen of them for five or six hours at a stretch.
After keeping these two nests under observation for a week we
excavated them both but failed entirely to follow the tunnel and
found none of the bugs that had been taken in.

This experience with unicolor took place in the middle of
July and we saw nothing more of the species for six weeks.
On the first day of September, however, one alighted almost at
our feet on the bare ground of the garden. She was much
smaller than the one that we had seen before, and the big, flat
bug that she carried was inconveniently broad and stretched
her legs apart as she ran about with it. After a moment she
went into a hole which did not in the least resemble the nests
of our earlier acquaintances, being much smaller and running in
obliquely, with no earth heaped around. This little wasp proved
to be one of the fearless kind and went on with her work with-
out noticing us. She, too,, had fits of industry. She sometimes
found a bug in ten minutes, but was usually gone from tliirty
to forty when on a hunting expedition. After working for an
hour or two she would amuse herself for the rest of the day,
sometimes staying out until sunset and sometimes going to bed
at half past one or two o'clock and remaining within until nine
on the following morning. The nest was invariably left open
when she went away but was always closed at night, and some-
times, also, when she went in for an hour's rest in the day time.

After we had watched this small unicolor for two days we
opened the nest but found only one bug and no egg. On the
next morning at nine o'clock she had nearly finished a new nest
close to the old one. She did no hunting during the morning
but made several excursions, and on returning from one of these
spent twelve minutes in searching for the new nest, coming
back again and again to the spot where the old one had been.
She began to hunt at one in the afternoon and took in three
bugs between that time and three o'clock, when she retired for
the night. One of these bugs was laid down at the entrance
of the nest while the wasp entered, turned around and then

90 THE SOLITARY WASPS.

came up head first and pulled it within. As a ucual thing-
unicolor walks straight in, carrying the bug in her mandibles.

Three of our four individuals of nnicolor excavated their
nests all at once instead of enlarging from day to day; but this
one, after making her nest on the morning of September fourth,,
was found early on the morning of the fifth excavating from
within. She worked in a very slow and dignified w^ay, without
the least hurry or bluster, loosening the earth and then lying
quite flat and pushing it out with the end of her abdomen.
Working backwards in this way she came out quite covered with
dust, and still lying flat, pushed the loose material away from
the entrance with her hind legs, but with a motion too gentle
to be called kicking.

The nest was opened on September sixth and tliis time the
tunnel w^as successfully followed, and four pockets, which led
off from it half way down, were discovered. (PI. XL, fig. 3.)
Three of these pockets contained partly eaten bugs, and one of
them had also a parasitic larva. The fourth pocket, which
seemed to have been most recently stored, contained three bugs,,
and on the venter of the last one taken in, near the base of
the first leg on the right side, and at right angles to the length
of the body, was an egg. We were surprised to find that such
a store of provisions had been taken into this nest, for if, as
we had taken for granted, it had been freshly made on Septem-
ber fourth by the wasp w^hose nest we had destroyed on the pre-
vious day, she had filled three pockets on the fifth and sixth, and
the bugs in two of these, as well as those carried in on the fourth,
had been partially destroyed,, not by the young of idiwolor, but
by parasites within their own bodies, before the sixth. We
concluded, however, that this was the case, since our only alter-
native was to suppose that this nest had been made by another
wasp, and that it had been partly filled before we saw it on Sep-
tember fourth, and it seemed extremely unlikely that anything
could have been Avorking there on the first three days of Sep-
tember without our seeing it. Moreover, if she was not the
wasp that we had been watching right along, why should she

THE BUG-HUNTERS. 91

have been attracted, as she evidently was, to the site of the old
nest?

The egg which we took ont on the sixth hatched just before
noon of the same day, so that the eg^ stage in this species is
probably not more than twenty-four hours. The larva ate the
three bugs provided, and spun its cocoon on September tenth.

On September seventh we found our fourth and last individ-
ual of Astata miicolor. This one, which was much larger
than any of the others, was making her nest when first discov-
ered, pushing out gi'eat quantities of earth with the end of her
abdomen. She was extremely tame at this stage of her proceed-
ings, allowing herself to be caught and examined, and then re-
suming her work without the slightest sign of fear or perturba-
tion. She worked slowly and deliberately for several hours and
made a large round hole. The earth that was heaped up around
the edges was not smoothed away and no effort was made to
render the nest inconspicuous, excepting that the spot chosen
was partly covered by a weed.

During the next few days our wasp did not spend much time
in the neighborhood of her nest. We occasionally saw her
going in or out but always empty handed. A beautiful big
green Clirysis fly was watching the course of events even more
closely than we were, spending her time around the nest or
even inside of it. When the proprietor came home the intruder
flew out and alighted close by. The wasp showed no resentment
and the fly no fear. Thinking that she might interfere with
our own designs we caught and executed the would-be male-
factor, only to see her place taken by a smaller fly of the same
family.

On September seventh our wasp was carrying in bugs, and
now we found that a great change had come over her attitude
toward us. Up to this time she had considered us as beneath
her notice, but when she began to provide food for her off-
spring we at once became objects of distrust and suspicion, and
nothing would induce her to go into the nest while we were
near. She flew about the place, frequently alighting and seem-

92 THE SOLITARY WASPS.

ing to hunt for it in different places. Sometimes slie would go
away for ten or fifteen minutes, and then reappear, still carry-
ing her bug, to resume her circlings, and it was not until we
had moved away to a distance of six or eight feet that she would
go in. This excessive timidity was in striking contrast, not
only to her former actions, but to the fearless conduct of the
small unicolor spoken of before.

Of three bugs taken from unicolor as she brought them to her
nest, two were quite dead, and the third, which responded to
stimulation by a quivering of the tarsi and the antennae when
it was taken, died the next day. This bug and another which
was taken dead from the nest excavated on September third, had
parasitic larvse within them which emerged after having eaten
the softer parts, but died without spinning any cocoon. The
three bugs taken intact from the nest opened on September sixth
were all dead, although they had been carried in only the day
before. Sq that although the sting that unicolor gives her vic-
tims does not always kill at once, it proves fatal within a very
short time.

Astata hicolor Say.
Plates L, fig. 4; IX., fig. 6.

It was one o'clock in the afternoon on the sixteenth day of
August. The mercury was trying some experiments up among
the nineties and we knew from experience that the lower garden
was the hottest place for miles around, yet thither we turned
our steps without a moment's hesitation, possessed by the idea
that something might be going on in that wonderful spot and
we not there to see.

Sheltered by our umbrellas from the burning sun we prom-
enaded up and down among the beans and potatoes scanning
every inch of ground. An hour passed and our enthusiasm
began to wane a little, yet we stayed on knowing that patient
effort is almost sure to bring a reward. Suddenly our attention
was arrested by a gleam of color. "Was it a fly, this brilliant
winged thing? Its actions awakened our interest; it had not

THE BUO-HUNTERS. 93

exactly the insouciant air of a fly. It aliglited near a weed,
rose, circled about a little, came back to tbe same place, rose
again, and — no, it was no fly, — dropped down into a tiny bole,
bidden from above by a leaf. It was a wasp, and a very pretty
one, with tbe abdomen soft, brigbt red, dark cepbalotborax and
gauzy wings. In a few minutes tbe little creature came creep-
ing out and began to circle around tbe place but sbe evidently
found it difficult to tear berself away from ber borne. Again
and again sbe aligbted near by, and finally sbe came close to tbe
opening and, flattening ber body so tbat sbe almost lay on tbe
ground, gazed into it in a contented and contemplative manner.
After a time sbe flew away. Sbe was gone for ten minutes and
wben sbe came back we saw tbat sbe was carrying sometbing in
her mandibles. Sbe did not go directly to tbe nest but aligbted
on a weed. After a moment sbe rose and circled about and
tben aligbted again, tbis time on tbe ground. After sbe bad
repeated these actions several times she entered the nest, de-
posited her burden and almost immediately came out again. As
before, some minutes were spent in circling about the spot be-
fore she flew away.

For two hours we sat by tbe nest watching ber as she pur-
sued the peculiarly even tenor of her way. Sbe hesitated, de-
layed, and circled about whenever she left home and whenever
she returned. Once on coming back to tbe nest, which was en-
tered by a slightly oblique gallery, she walked in over the upper
edge so that her back was down. On her return from her
fourth journey we caught her in a bottle and found that sbe
was carrying a small bomopterous insect, which she held by tbe
bead, venter up. We shook the bottle but she would not drop
it, and when released she resumed the business of the day with
perfect self-possession. Twice on going in, she pushed up some
earth, thus closing the hole behind her.

In the two hours that we watched her sbe made ten journeys.
The stay within tbe nest was never more than two minutes but
often as much more time was spent in going in and in getting
away. "We kept a record of the hours at which she returned

94 THE SOLITARY WASPS.

wliich reads as follows: 2:42 o'clock, 3:03, 3:10, 3:18, 3:25,
5:30, 3:46, 4:00, 4:08, 4:15.

At fifteen minutes after four the wasp thought that she had
worked long enough and as we were beginning to have something
of the same idea it was a relief to find that having closed her
-door behind her she had gone to bed, or at least had decided to
pass the evening at home. After awaiting for some time to
see if she would reappear we placed a blade of grass over the
nest, and covering all with an inverted tumbler, bade her good
night.

At half past seven o'clock on the following morning we vis-
ited the garden to see if our little wasp was yet awake, but the
blade of grass had not been disturbed. On a second visit, at
nine o'clock, we found her flying about inside the tumbler and
at once released her. She flew off and was gone for an hour
and when she returned, bringing nothing with her, she circled
about for a short time and then again departed without entering
the hole. Ten minutes later she came back, still empty-handed,
went into the nest, and pushed up such a quantity of earth from
below as to make quite a high mound in place of the opening.
When she came out again this accumulation of earth spread
itself out on all sides. She now began to enlarge her nest, car-
rying out the dirt in little pellets, but this fit of industry only
lasted for six minutes. A contemplative mood overtook her.
She certainly felt no pressure of necessity, being quite contented
to rest on a neighboring weed and meditate, varying the mo-
notony by occasionally circling about her nest. It was two
o'clock in the afternoon before she resumed her hunting expe-
ditions.

This was our first acquaintance with Astata hlcolor. A late
arrival on the scene, it soon became a common species and be-
tween this time and the first of September scarcely a day passed
without our seeing it. We never witnessed the making of the
nest from the beginning but probably the earlier as well as the
later part of the work is done with the mandibles, unaided by
the legs. Supposing the excavation to be begun about ten

THE BUO-HUNTEES. 95

o'clock in the morninsr, the work is carried on without haste and
with frequent pauses until two or three in the afternoon, when
it is suspended. Bicolor goes in for the night at about four
o'clock and nothing more is seen of her until the next morn-
ing when about an hour's labor completes the nest.

She invariably leaves the nest open when she goes away, but
in every case that came under our notice the spot chosen was
protected by the branches or leaves of some weed so as to be
invisible from above. She is rarely fortunate in one respect,
since we have never seen a parasitic fly in attendance upon her;
but this fact makes it difficult to explain her wily and cautious
approach to the nest. Why should she spend so much time in
getting in, scarcely ever dropping directly down to it as other
wasps do? On entering she often leaves the hole open and just
as often closes it. The closure at night is doubtless to protect
the nest from cold and dampness but in day-time it may be
merely the result of her pushing back the loose earth which
bars the passage to the nest. There is no attempt to clear away
the earth from the outside. The appearance of the nest is al-
most identical with that of an ant-hole, a tiny opening with a
circular heap of earth around it. The entrance tunnel is from
two and one-half to three and one-half inches in length and the
nest itself is from one and one-half to two and one-half inches
below the surface.

In one of the nests that we opened we found three bugs.
These we put into a glass with the wasp that had taken them
in. She took each one in turn, and, standing over it, venter to
venter, squeezed its neck very slowly for half a minute or more.
We offered her several live specimens of the same species but
she would not touch them. Of those that were taken from the
nest, one was injured in being taken out, one was nearly dead
and the third was very lively. The second one lived three and
the third one five days after wei disinterred them.

At another time, having found a wasp that was provisioning
lier nest, we waited until she went in with her load and then
placed over the opening an inverted tumbler containing seven

96 THE SOLITARY WASPS.

live bugs of the species that she preferred. When she came
out she flew about in the glass for a short time and then, seiz-
ing one of the bugs by the head, in her mandibles, and holding
it dorsum up, she curved her abdomen under it and stung the
lower face of the thora:x. We were close by, and could see the
performance distinctly. She then, without relaxing her hold,
walked with the bug into her nest. We tried to get her to take
another, but without success.

Wishing to follow the fortunes of this wasp still further we
came down to the garden early the next morning and stationed
ourselves near her nest. It was nine o'clock before she made
her appearance, and then she spent half an hour in the imme-
diate neighborhood, walking around and around and frequently
flattening herself down in the dust. She then went away, per-
haps for breakfast, coming back an hour later without any load
and spending twenty minutes inside the nest. At the end of
this time (it was now eleven o'clock) she began the business of
the day by working for ten minutes at enlarging her nest.
Then, after circling about and alighting again and again, after
standing just inside the doorway and looking out, and after ly-
ing down just outside the dooi-way and looking in, this most
calm, deliberative, and unhurriable of all the wasps went away
and caught one bug. After that the charms of home again as-
serted themselves and the circling performance was repeated.
We tried to get her to accept a bug of our providing, but in
vain. At half after eleven she took her departure and three
hours later she had not returned. We then opened the nest
(PL IX., fig, 6) in which we found eighteen bugs, thirteen of
them being dead and five living as was shown by the quivering
of their legs and antennae in response to stimulation. They were
all mixed with earth but had doubtless been stored in pockets
like those ®f unicolor. We found no eggs nor larvae. Of the
five living bugs two died within twenty-four hours, while the
others lived three days.

We saw another of these wasps carry in nine bugs during an
afternoon and the following morning. Once, when she came

THE BUO-HUNTERS. 97

out, we placed a large bug near her. She seized it promptly
and stung it on the under side of the thorax as in the other case,
and then carried it into the nest. We saw no malaxation, but
this, perhaps, was done inside.

One afternoon we saw a little female of this species dig a
very shallow nest, which she then entered, closing the door be-
hind her. This was probably only a temporary shelter to be
used for the night.

Astata McoJm^, with her dreamy ways and reflective turn of
mind seems out of place among our restless Ammopliilae,
Sphegidae, and Benibecidae. Her character is distinctly Ori-
ental, and nothing of the huny of the West is seen in it. As
might be expected the individuals of the species do not differ
from each other as is the case with other wasps. We found a
remarkable unanimity in their hours for rising and retiring, and
in the manner of digging the nest, in the result accomplished,
and in their habits of departing and returning, each one was
like all the rest.

So far as the habits of Mcolor have a bearing upon the ques-
tion of the stinging instinct, they show that there is no exact
surgery involved in her method of dealing with her prey. She
stings in the thoracic ganglion, and as a usual thing she stings
to kill. It, may be that in some cases malaxation is substituted
for stinging, for a few of the bugs taken from the nests seemed
too lively to have been subjected to so serious an operation.
The second conclusion to be drawn is that the larva of hicolor
subsists principally upon dead .bugs. There is no wonderfully
preserved store of fresh provisions for this little plebeian. Bugs
can scarcely be considered dainty fare under any conditions and
how much less so when they have been dead for days! Yet
this is certainly a flourishing species, bearing no marks of de-
generation or decay.

98 THE SOLITARY WASPS.

Astata Leuthstromii Ashmead.

It was on the foiirteentli day of July tliat we saw this new
species whicli is a little longer than hicolor and dark in color.
The wasp stood with her head peeping out of a hole that seemed
too large for it, and occasionally scrambled on the edges with
her fore feet as though she were trying to get out, although it
may be that her object was to draw loose dirt down into the
hole. There was no heap of earth around the place as with
the nest of hicolor. After a little the wasp came out and flew
away but returned, without a load, in ten minutes, and after
alighting and walking about for a while, flirting her wings as
she moved, went in and closed the door. It was now three in
the afternoon, and she did not open the nest until a little before
nine on the following morning. The place was shaded and
perhaps for this reason she did not go out at once, but she came
up every few minutes and looked about, not jerking her head
this way and that as is characteristic of some of our wasps, but
frequently wiping in a little dust with her antennae.

At the end of an hour she flew away without circling. In
ten minutes she came back, flying lightly although she carried
a bug in her mandibles, and after alighting for a moment on a
blade of grass, flew into her nest, passing her burden backward
as she entered so that for an instant it projected behind her.

Fearing that we might lose our wasp if we let her go again
we captured her as she came out, and excavated the place, but
failed to trace the nest or to find the hidden treasure.

THE DIODONTI. 99

CHAPTEK X.

The Diodonti.
Plates X., fig. 5; XIV., fig. 3.

Along the fence that separates the garden from the woods be-
yond grows a row of choke-cherry bushes, among which are
mingled wild roses and the tall stalks of the yellow coreopsis, —
a touch of poetry amid the prose of beans and potatoes. It was
while passing these bushes one day early in July that we saw,
hovering over them, numbers of little black wasps. These were
the Diodonti, and closer inspection showed that they were busily
engaged in catching the aphides which swarmed on the under-
sides of the leaves. We were glad enough to seize the oppor-
tunity thus offered, and for this and several succeeding days we
devoted ourselves to the study of this fearless and friendly little
species.

Diodontus americamts is one of the tiniest of all the wasps,
but having chosen for its prey something still smaller and weaker
than itself it never lacks good hunting. Yet the wasps and the
aphides were not the only actors in our modest drama of the
choke-cherry bushes. The ants were also on hand, solicitously
tending their little green cattle.. As might be expected they did
not look upon the destruction of the aphides with indifference
but gave practical proof of their interest in the matter by driv-
ing away the attacking wasps. Had they combined, and sent
out detaclmients to protect their flocks, the Diodonti might have
hunted in vain, for the wasps invariably had the worst of it in
their encounters with the ants; but their efforts were solitary
and did not count for, much, since a wasp that was driven from
one group at once settled down upon another.

In Belt's '^Naturalist in Nicaragua" there is an interesting

100 THE SOLITARY WASPS.

account of a similar state of things existing among wasps, ants,
and frog-hoppers. He tells of one species of ant which has
adopted the role of protector, and which feels its responsibilities
so thoroughly that it will bite the hand of any one who inter-
feres mth the young frog-hoppers. He says, "These leaf-hop-
pers are, when young, so soft-bodied and sluggish in their move-
ments, and there are so many enemies ready to prey upon them,
that I imagine that in the tropics many species would be exter-
minated if it were not for the protection of the ants.

"Similarly as in the Savannahs, I had observed a wasp attend-
ing the honey-glands of the buU's-horn acacia along with the
ants; so at Santo Domingo another wasp, belonging to quite a
different genus (Nectarina), attended some of the clusters of
frog-hoppers, and for the possession of others a constant skir-
mishing was going on. The wasp stroked the young hoppers,
and sipped up the honey when it was exuded, just like the ants.
When an ant came up to a cluster of leaf-hoppers attended by
a wasp, the latter would not attempt to grapple with its rival on
the leaf, but would fly off and hover over the ant; then when
its little foe was well exposed, it would dart at it, and strike it
to the ground. The action was so quick that I could not deter-
mine whether it struck with its fore-feet or its jaws; but I think
it was with the feet. I often saw a wasp trying to clear a leaf
from ants that were already in full possession of a cluster of
leaf-hoppers. It would sometimes have to strike three or four
times at an ant before it made it quit its hold and fall. At
other times one ant after the other would be struck off with
great celerity and ease, and I fancied that some wasps were
much cleverer than othei"S. In those cases where it succeeded
in clearing the leaf, it was never left long in peace; for fresh
relays of ants were continually arriving, and generally tired
the wasp out. It would never wait for an ant to get near it,
doubtless knowing well that if its little rival once fastened on
its leg it would be a difficult matter to get rid of it again. If
a wasp first obtained possession, it was able to keep it, for the
first ants that came up were only pioneers, and by knocking

THE DIODONTI. 101

these off it prevented them from returning and scenting the
trail to communicate the intelligence to others."

With our wasps there was no such struggle as this for the
possession of the aphides. They made no resistance and we
never saw them try to strike the ants from the bushes. We
have been especially interested in Mr. Belt's opinion that some
wasps are much cleverer than others as we have again and again
noted the same thing.

We found that when a wasp secured an aphis she flew with
it to another leaf near by, alighting, this time, on the upper
surface. She then passed it back from her mandibles to the
second pair of legs, and holding it, with them, under her body,
she proceeded to make use of the first pair in giving herself a
thorough cleaning. Her face, especially, was well washed and
rubbed. We afterward saw other wasps put themselves in
order and smooth their ruffled plumage after catching their
prey. Ammophila was especially given to making her toilet
on these occasions, but she had some excuse for it since she
could not subdue her victim without going through something
of a struggle. With Diodontus the performance became
absurd, since the capture of the aphis required no combat,
scarcely, indeed, an effort. The victim was merely picked up
and carried off.

Her dainty person being put to rights, our little vv^asp brought
the aphis forward, and squeezed its neck repeatedly between her
mandibles. With Diodontus this malaxation is always accom-
plished delicately, so that the. skin is not broken, but there is a
considerable variation in the thoroughness of the work. In
most cases the aphides are killed, since we afterward found that
they were almost invariably dead in the nests, even in those that
were freshly provisioned. In other cases the disturbance was
so slight that they were able to walk about as soon as they
were released, seeming to be scarcely injured.

To see the whole process more conveniently we repeatedly
caught a wasp and placed her in a bottle with a leaf upon
which were aphides. Using a glass, we could then see what

102 THE SOLITARY WASPS.

passed very distinctly. The tiny wasp would pounce upon an
aphis, and holding it with the first legs would squeeze its neck
gently between the mandibles, rolling it over and over. After
a few moments she would pass the aphis back to the second
pair of legs and rest for a short time, usually taking this op-
portunity to wash her face. She would then bring the aphis
forward and squeeze it again. After several repetitions of this
process, the apliis would be dropped and another one picked up
to be dealt with in the same way, twelve or fifteen being taken
in succession before the wasp tired of her objectless industry.
In the open, Diodcnitus often alights on one leaf and malaxes
her victim and then flies to another and another, repeating the
process several times before she finally flies off to her nest.

We were surprised to find that the wasp never used her sting.
Since death is to be the result it would seem that the end could
be attained more easily by the injection of a drop of poison than
by the careful and laborioLis process which is used. This is
not from any rigidity of the abdomen, since while we were
handling the wasps they repeatedly tried to sting us, although
they are such tiny creatures that they were unable to puncture
the skin. It would be of interest to know whether Stigmus,
which also captures aphides, and Rhopalum and Crahro, which
take gnats, use their stings in killing their prey. We have seen
the vigorous Polistes fusca descend upon a caterpillar and
reduce it to a pulp by squeezing all the parts with her mandi-
bles, not condescending to use her sting at all. It may be
that this is the common method of capture in all those cases in
which the difference in size and strength between the two
actors in the pl^y is such that the wasp need not sting her victim
in order to reduce it to helplessness in her hands. This idea
suggests that the object of the stinging is primarily to subdue,
not to paralyze.

The next question that confronted us was, where were the
nests of Diodwitusl Here we met a difficulty that seemed
absurd enough later on but which was very real at the time.
We watched the wasps carefully as they prepared for flight, and

THE DIODONTI. 103

bent all our energies upon keeping tliem in view — in vain. They
rose upon their wings, and disappeared. Baffled again and
again, we called the children of the household to our aid and
offered prizes for the discovery of the nests, and these recruits,
thinking that perhaps the wasps crossed the garden to the barn-
yard, searched that enclosure thoroughly, and found in the straw-
stack, nests indeed, hundreds of them, only they belonged to
Trypoxylon. Not discouraged, our energetic assistants next
scrambled over the fence to the north, invading the woods, and
there in a worm-eaten weather-beaten stump they found more
nests — but they belonged to Rhopalum and Stigmiis. Three
days passed before we dropped our eyes to the ground at our
feet and found that there, close by, were the abiding places of
Diodontiis.

From the outside the nests show a tiny hole with some grains
of dirt irregularly heaped around the edges. We had the great-
est difficulty in excavating them, as the crumbling earth fell into
the narrow gallery at every touch, making it almost impossible
to trace. The nest that is shown in the drawing had been
started in a small lump of earth which lay on the ground, and
this made it easier to follow the entrance tunnel. (PL X.,
•fig. 5.)

It takes the wasp about an hour to dig her nest. She carries
the earth out with her mandibles and first legs, backing from
the hole. The gallery runs in obliquely and ends in a pocket
to one side. The nest is not closed until the provisioning is
completed .

When an aphis is brought home the wasp remains within the
nest only a few moments and then is off in search of another.
The egg is not laid on the first one brought in since it is often
lacking in nests which contain six or eight aphides. If the
weather is hot and sunny it is not unusual for a nest to be made
and completely provisioned on the same day, but when it is cool
or cloudy americanus works very slowly or not at all. About
forty aphides are necessary for the provisioning of a single nest.

On the same bushes with these wasps we constantly saw a

104 THE SOLITARY WASPS.

slightly larger species of Diodontus which acted in every way
like americanus. In spite of all our efforts we were unable to
find the holes of this second and larger species. They were
present in large numbers and it seemed improbable that they
could have nested in territory so familiar to us as the garden
came to be without being discovered. After close watching we
concluded that these wasps flew over the fence into the woods
while americanus settled down close by.

The month of July is evidently the working season of the
Diodonti since they were very active from the seventh of the
month, when we first saw them, until the first of August. From
that time on we saw them less and less, although a few of them
were still at work three weeks later .

On July twenty-fifth we first saw the males of this species^
which, Mr. Ashmead tells us, had been unknown before. On
this and on succeeding days we saw them mating with the fe-
males. As the females had been laying their eggs for about
three weeks the males had probably been present all the time,
but had escaped our attention.

The parasitic Chrysis fly, Omalus corruscans, is always in at-
tendance upon americanus, both on the cherry bushes and on
the ground near the nests. Brilliant and beautiful but full of
evil intentions, she watches their comings and goings. There is
no opportunity for her to lay her egg on the aphis outside of
the nest. Holding it closely under her body and not exposing
any part to attack, the wasp, without making the least pause,
flies into her open doorway. When she comes out again the
enemy is still lurking near, but no instinct warns her to cover
her treasure. The door stands wide open as she takes her de-
parture, leaving her young exposed to the foe. Perhaps the
danger is not so great as it seems. The fly certainly penetrates
into the nest, since we have found it in the gallery when exca-
vating; and in one case we found a strange larva feeding on the
aphides along with that of americanvs; but it may be that the
supply of food is so ample as to cover the needs of both. At

THE DIODONTI. 105

any rate it must be confessed tliat tlie parasite has not prevent-
ed americantts from becoming a flourishing species.

Although as a rule, Diodontn^ worked for the coming gener-
ation, the captured aphis sometimes served not as food for the
young but as a dainty morsel for herself. In these cases there
was no malaxation, the aphis being held in any position while it
was sucked dry of all its juices and then thrown away. This
may be a further development of the habit described by Belt of
stroking the frog-hoppers to get the drop of honey which they
can yield without harm to themselves. It has little in common
with the method of PMlanfhvs apivorus, which, according to
Fabre, squeezes the honey from its bee because if left, it would
prove fatal to the young larva. It is rather like that of Ody-
neriis nidulator which takes nothing from the caterpillars
which are destined to feed the young, never storing up those
from which it has sucked the juices.

Cerceris omata offers us still another habit. The neck of
HaUctus, its prey, is brutally compressed, the skin being broken
so that the juices of the body exude, and these juices are licked
off by the wasp.* The object of the malaxation, however, seems
to be to produce lethargy for the benefit of the wasp larva, since
the bee is afterward stored up. The taste that the wasp gets of
bee-juice is rather an accident than anything else. How is it
that thei honey is not fatal to the young of Cerceris, as it is to
that of Philantlmsl

As has been said, the excavation of the nest of Diodontus is
a difficult matter, but in six cases we succeeded in finding the
pocket with its contents. In these nests the number of aphides
varied from five to forty, the provisioning being only just begun
in some cases while in others it had been completed, and the
nest closed up.
, With a single exception the aphides in these nests were dead.
They were usually green when first taken out but turned yellow

*Etiide sur 1' Instinct du Cerceris ornata, Archives de Zoologie Ex-
perimentale et Generale, Deuxieme Serie, Tome V., 1887, p. 27.

106 THE SOLITARY WASPS.

by the second or third day and by the fourth or fifth were all
dry and brown. The exception to the nile was a very lively lit-
tle aphis found in a closed nest with about forty dead ones. We
have no doubt that they are often aliye when first taken in, from
the fact that while watching the action of the wasps in the bot-
tle we noticed that they not infrequently left the aphides al-
most uninjured.

In four of the nests we found the egg, which in one instance
was on the under side of the body of the aphis, while in the
other oases it was placed on the dorsum. Perhaps one of the
eggs was laid by a parasit-e and this was the reason of the dif-
ference in position.

Only two of the eggs hatched. The first of these (ISTo. 23)
was taken from a nest which had been closed up at three in the
afternoon on July twenty-second. At nine in the morning of
July twenty-fourth we found that it had hatched, and it seemed
to be a few hours old. The egg stage, then, probably lasts
about thirty-six hours, although we judge that it may in some
instances be less from the case of another wasp, ]S"o. 24. This
nest was also closed up by the wasp on July twenty-second, and
we dug it up on the afternoon of the same day. The larva,
however, hatched at nine in the morning of July twenty-third,
nearly a day sooner than the one in nest No. 23. This, to be
sure, may have been due, not to a more rapid development of
the egg, but to its having been laid earlier, perhaps shortly after
the provisioning of the nest was begun, while in the other case
it may have been laid after thei aphides had all been carried an.
We know that in certain other wasps {Pelopaens) there is just
such a variation as this in the point of time at which the egg is
laid.

These two wasplings lived through the six days of their larval
life. They ate the whole aphis, leaving no debris. At the end
of that time one of them died and the other spun its cocoon. In
the tube with this later larva we discovered, on the seventh day
after the nest was taken up, a second smaller larva which was
also eating the aphides. This one, which was probably the

THE DIODONTI. 107

young of O. corruscans, disappeared two days later witliout
having exerted any evil influence upon the destiny of the right-
ful owner of the nest.

Diodonttis gracilis and corniger are said to provide aphides
for their young, making their nests in holes in posts, while
minutus and tristis, like americanus, burrow in the ground.
Americanus seems to be the only American species of which
anything is known.

108 THE SOLITARY WASPS.

CHAPTER XI.

SOME GRA\^ DIGGERS.

Cerceris and Philanthus.
Plates L, figs. 3 and 8; VIII., fig. 6; IX., fig. 1; XL, fig. 2.

Dufour, in describing tlie fearful ravages of Cerceris ornata
among the bees, says that tlie wasps of this genus are among
other insects what eagles and hawks are among birds. While
this characterization does not seem to fit the American species
it is certainly true that the genus stands out as one of those in
which the distinctive peculiarities are strongly marked. They
might be considered the aristocrats in the world of wasps, their
habits of reposeful meditation and their calm, unhurried ways
being far removed from the nervous manners of the Pompilidae
or the noisy, tumultuous life of Bemhex. Their intelligence is
shown by their reluctance to betray their nests, and by their un-
easiness at any slight change in the objects that surround them.
It is not necessary to attempt to catch them, or to make threat*
ening gestures in order to arouse their sense of danger. If you
are sitting quietly by a nest when the wasp opens her door in
the morning she will notice you at once and will probably drop
out of sight as though she resented your intrusion into her pri-
vacy. After a little she will come up again and will learn to
tolerate you, but at the least movement on your part, almost at
the winking of an eyelid, shq will disappear.

Our three representatives of this genus all prey upon beetles
that are injurious to vegetation, and therefore deserve the grat-
itude of the agriculturalist. They are from one-half to three-
quarters of an inch in length, clypeata and deserta being band-
ed with bright yellow, while in nigrescens the bands are rar.cb
paler, being gray with a faint tinge of yellow.

SOME GRAVE DIOGEES. 109

The nests of our species are all deep, tortuous, and very
•difficult to excavate. We have never succeeded in finding their
pockets and yet, for various reasons, we feel perfectly certain
that nigrescens, deserta, and clypeata are like C. orna-
ta in provisioning, successively, a number of cells which lead
out of the main gallery. When one of these cells is filled with
food and the egg deposited, it is probably closed up and thus
separated from the runway. From our experience late in the
season with the nests of another wasp (Astata unicolor) we are
inclined to think that we made a mistake in looking for pockets
at the lower end of the tunnel. Had we searched higher up, at
the point of the curve, we might have found them, the lower
part of the gallery probably being designed merely for a dwell-
ing place for the mother of the family.

But although we did not get distinct pockets we found, in at
least one nest, a supply of food that would have far exceeded
the wants of a single larva. We did not succeed in finding dif-
ferent eggs on different groups of beetles but in a nest into
which the wasp was still carrying food we found a half grown
larva which was identified as being hers. The fact, too, that a
wasp occupies a nest for so long a time as ten days or two weeks
points to the conclusion that she uses it for a number of eggs
which are laid at intervals.

Cerceris digs her nest, deep ag it is, all at once. In this she
is a contrast to her near relatives of the genus PhilantJms who
busy themselves for an hour or so every morning with fresh ex-
cavations.

Cerceris clypeata Dahlborn.

Plate I., fig. 8.

On the eighth of July the weather was so warm and bright
that we went down to the garden at half past eight o'clock,
knowing that it was rather early but hoping that the hot
sunshine would tempt the wasps to industry. We had walked up
and down several times when suddenly, right in the pathway, a
nest appeared. A great quantity of loose earth had been taken

110 THE SOLITARY WASPS.

out and heaped up, probably on tbe preceding day, and in the
midst of tbis a little bole bad been opened since we passed be-
fore. Tbe place looked so promising tbat we sat down to watch
it, and a few minutes later we were rewarded by a glimpse of
some antennae down tbe gallery, and tben a little face witb yel-
low markings appeared but quickly vanisbed. I^ow followed a
very coquettish performance. Tbe wasp came slowly creeping
up again and again only to drop out of sight as soon as she bad
reached the opening. After a time she grew bolder and sat in
her doorway, twitching her head this way and that in a very
expressive manner as though she were planning the work of the
day, but it was plain that although she was up early, business
cares were not weighing heavily upon her mind, for forty min-
utes passed before she came out of the nest, and after making
three or four circles about the spot, flew away.

How much livelier an'^. more interesting it would have been
if we could have followed her! We tried to guess at what she
was doing, and imagined her bunting industriously. After
fifteen or twenty minutes it seemed to us tbat she must have
caught something and tbat she was surely returning. Most
probably she was not working at all, but was breakfasting lei-
surely and exchanging compliments with her neighbors, for
when she did come home after keeping us waiting for an hour
and a, half, she brought nothing witb her and seemed quite un-
conscious of the fact that greater things had been expected of
her.

We bad placed a stone upon a dead leaf near by, to mark tbe
neighborhood of tbe nest, thinking tbat even a Cerceris could
not object to so simple an arrangement of natural objects, but
our wasp noticed it at once, and evidently with much suspicion
and disapproval. She began by circling several times just
above it. Tben she alighted on it and examined it carefully,
walkins: over it and creeping underneath, perhaps to see whether
it in any way menaced the safety of her nest, perhaps as tbe
completion of a locality study made tbe day before. She tben

SOME GRAVE DI GOERS. Ill

rose on lier wings, and after a little more circling, dropped sud-
denly into her hole.

So far we had not been getting on very rapidly but from this
time things took a turn. Cerceris is never in a hurry and yet
she may be relied upon to do a certain amount of work every
day. The one that we were now watching had probably come
back for a final look at her newly made nest before beginning to
provision it, for she soon reappeared and this time really went
to work since in forty minutes she brought home a beetle (Bal-
aninus nasicus Say.), which she carried by the snout, venter up^
in her mandibles, supporting it while flying with the second pair
of legs. She was much annoyed at our presence and circled
about as before. Twice she alighted near by and walked about
for a few minutes, and when she did this all her feet came down
to the ground, the beetle being allowed to hang loosely. At
last she made the best of a bad matter and went in. The rest
of the morning was occupied with hunting, the capture of each
beetle taking about forty-five minutes. Every time that she
came home she spent fifteen or twenty minutes in the nest.

This species soon became very common and for two weeks
scarcely a morning passed without our finding at least one newly
made nest. The study of clypeata, however, consumes a great
deal of time. For example we found, one morning, two nests
within six inches of each other. It turned out afterward that
these were; inhabited by two different wasps, but at the moment
we supposed that one of them had been dug and deserted and
then a second one made, and wishing to know wliich one was
occupied we resolved to watch and see. After waiting for
three hours we saw one wasp returning but upon noticing us
she veered off and began to circle about. She was heavily laden
and her burden, instead of being supported by the second pair
of legs, as is sometimes the case, hung down under the thorax
and abdomen. After a moment she alighted on a plant near by
and seemed to consider the situation, then circled a Httle more
and flew away, remaining out o£ sight for fifteen minutes, then

112 THE SOLITARY WASPS.

another return, more circlings and hesitations. She seemed to
feel the weight of the beetle now, and alighted frequently on
the ground and walked about, jet she would not go in, so reluc-
tant was she to betray her nest. In this way she kept us wait-
ing for a whole hour, although w^e were not sitting very close
and were as still as statues. At last we retreated and stood as
far back as we could and still keep the hole in view. She now
came closer, and, after hanging poised on her wings for a mo-
ment, dropped into her nest.

We once found a nest of this species in process of construc-
tion. A large heap of fresh earth had been pushed out and
this entirely covered the spot, but at intervals there were up-
heavals from below which betrayed the presence of the wasp.
When we saw it first it was half past eight o'clock, and we
judged, from what had been accomplished, that she must have
been at work at least an hour. It was half past nine before
the excavation was complete. We had not been certain, up to
this time, as to what w^e were watching, but now we had the
pleasure of seeing her open her doorway from below and stand
in the entrance wliile she washed her face, very prettily. When
they rest at the mouth of the hole the first legs, which are yel-
low, are bowed in a semi-circle on each side of the yellow face,
the distal joints being bent up so that the wasps seem to be
standing on their elbows. This attitude, which is often seen
in Bemheco spinolae, gives them a delightfully amusing, bow-
legged appearance. They usually open their nests in the morn-
ing at about nine o'clock, — a little earlier or later according
to the time at which the sun strikes the spot. They then spend
from forty minutes to an hour in taking a sur\'ey, the least
movement on the part of a watcher causing them to drop out
of sight as if the earth had given way beneath them. Some-
times there is a little way-station an inch or two -within the tun-
nel, and the wasp only falls back to this point, and here she may
be seen, if one peeps in cautiously, either quietly awaiting the
retreat of the intruder or, perhaps, performing her toilet in a

SOME GRAVE DIOGERS. 113

leisurely and elegant manner, using her fore feet, like a cat, to
wasli her face.

Whenever she leaves her nest she makes three or four rapid
circles around the spot. This is doubtless to freshen her mem-
ory of the locality. We once saw clypeata make a thorough
study of the neighborhood. This was in the case of the wasp
mentioned before, that was so long in carrying her beetle in be-
cause of our being on the ground. When she finally did go in
she stayed only an instant — just long enough to deposit her
load — and then came out and spent a long time in a thorough
investigation of all the surrounding objects, flying in and out
among the plants, now high, now low, and circling again and
again around the spot. It looked as though she had been puz-
zled and disturbed by the presence of unaccustomed things. As
soon as the sur\'ey was over she went inside and closed the door,
as though its object had been not so much to strengthen her
memory as to correct former impressions.

The work of bringing in beetles goes on very irregularly, and
as a rule not more than two or three are stored in the course of
a day. It is not unusual for clypeata to spend three or four
hours away from home and then come back without anything,
and often, even in the middle of the day, she passes an hour or
twoi in the seclusion of her nest. We had several nests under
observation for a week at a time without ever once seeing the
owners, although they were evidently occupied since they were
sometimes open and sometimes closed. The outer entrance is
always left open when the wasp goes away, although possibly
access to the pockets may be barred below; but when she enters
she closes the door unless she means to come out again at once.
The closing is sometimes effected by pushing the earth up back-
wards, with the end of the abdomen, but the hole is rather too
large for this method and more frequently the wasp comes up
head first, carrying a load of earth in her front legs. This is
placed just within and to one side of the entrance, and then
more armfuls are brought up, until, after two or three trips, the
opening is entirely filled.
8

114 THE SOLITARY WASPS.

We once captured tlie wasp in a bottle, as slie returned, load-
ed, to the nest. Slie dropped the beetle but soon picked it up
again and stung it vigorously, icitli intention, as the French
say, first under the neck and then further back, behind the first
pair of legs. After this it was dropped while the wasp fluttered
about for a few minutes, but it was then picked up again, and
stung as before. We both saw this operation repeated in exact-
ly the same way, four different times, with intervals of five or
six minutes between.

In a nest which we excavated after watching it for nine days,
we found nothing until we had gone six inches down, and at
this point the tunnel was lost, but mixed with the crumbly earth
that we took out of the hole, we found eight beetles and a
half grown laiwa of clypeata. The destruction of this nest was
accomplished one morning, and when we came back to the spot
twenty-four hours later we found that a new one had been
made close by, doubtless by the same individual. We had ex-
pected to find her bringing beetles and dropping them foolishly
on the ground like Paul Marchal's Gerceris ornata, and were
gratified that she showed an advance in intelligence over that
species, although to be sure she would have been still wiser had
she chosen an entirely new neighborhood. Another individual
was so much disturbed by our scrutiny that she dropped her
beetle at the entrance to her nest. She did not pick it up again
and utilize it, although it lay for three days in the dust at the
threshold.

As to thei condition of the beetles stored by clypeata, in the
first nest that we opened we found eight, seven of which were
dead, while the eighth, which we had just seen stung several
times, was alive but died on the following day. The second
nest gave us five beetles^ all of them dead and dry. In the other
nests that we opened we found nothing, although we knew; that
the beetles were there had we only been skillful enough to dis-
cover them.

SOME GRAVE DIGGERS. 115

Cerceris deserta Saj.

Of this species, wMch. closely resembles clypeata but appears
later in, the season, we had only a single example. We chanced
to see her dropping into a crevice among come lumps of earth
and at first could scaieely believe that this was the dwelling
place of a wasp, as there was nothing whatever about it to in-
dicate a nest, and even after we had removed the rough pieces
of earth above, we could see nothing of the loose material that
must have been carried out.

She was much like clypeata in her manners, with the same
habit of surveying the world from her doorway and manifesting
the same annoyance at our presence when she was returning to
the nest, but she carried in more beetles in the course of the day
and worked much more rapidly. Between nine and eleven
o'clock one morning she brought in five loads, and some of the
journeys occupied only ten minutes.

The first time that she found us sitting by her nest she circled
about for nearly an hour, seeming unable to make up her mind
to enter. At length we withdrew a little way but still her sus-
picions were not entirely allayed, and after a further study of
the situation she dropped, not into her own nest but into a large
cricket hole near by. Taken aback by this manoeuvre, and
thinking that perhaps we had a second individual to deal with,
we stealthily approached, and peering in, could see the cricket
inside, the wasp having slipped beyond. It did not seem pos-
sible that the little creature could be endeavoring to deceive us,
and yet what other explanation could be offered for her con-
duct? "We again took up our distant position, and after ten
minutes more had the satisfaction of seeing the wasp slip out of
the false nest and drop instantly into the true one. After a
little she became quite accustomed to us and entered her nest
without the least delay.

The prey of deserta (Conotrachelus posticatus Boh.) is held
in the mandibles, and while we were watching her she did not
support it with the second legs, even when flving. We took

116 THE SOLITARY WASPS.

one of these beetles from lier and found that it moved the tip of
the abdomen freely whenever the body or legs were touched. On
the next morning only the tips of the legs responded, by quiver-
ing, when the body was touched, and two days later it was un-
questionably dead.

This species sometimes makes quite a thorough study of her
nesting place before lea-\ang it, and then, again, she will fly off
without pausing at all. She has the habit of making a number
of half circles in front of the spot, and then, after rising a little
higher, of flying several times completely around it.

The observations on deserta were made between the twenty-
fifth and twenty-ninth of August.

Cerceris nigrcscens Smith.

We had long been familiar with the sight of nigrescens flying
about over the purslane plants, now alighting and now circling
again, before we succeeded in getting close enough to see what
she was doing. What we had sought for in vain, however, came
to us unasked. We had just entered the garden, one afternoon,
when we saw her, bearing some kind of a burden, drop into an
open hole almost at our feet. After a few moments she came
out and flew away, and we, making ourselves as comfortable as
circumstances permitted, settled down to watch the course of
events.

Forty minutes passed before we saw her returning. She was
evidently caiTving a load which she seemed to" hold in her man-
dibles. She seemed much annoyed by our proximity to her
nest, and it was fifteen minutes before she could make up her
mind to go in. During this time she circled about within from
five to ten feet of us, alighting frequently on the weeds. Once
when she alighted her victim seemed to stiniggle, for she
pounced on it and grasped it afresh. She finally dropped into
her nest and at once pushed, up a large quantity of earth behind
her. As she had not done this the first time that we saw her go
in we took it as an indication that she meant to remain at home
for the rest of the afternoon, and this proved to be the case.

SOME GRAVE DIGGERS. 117

We watched patiently but she did not come out, and at the end
of half an hour we covered the spot with a glass, first marking
the nest by scattering grass seed over it. These seeds had not
been disturbed at sunset, and as the nest had been closed at half
after two o'clock it was evident that she had firjshed her day's
work at that hour.

On the following morning we were on hand at an early hour,
but nigrescens did not appear until nearly nine o'clock, and
then it was only to put her head outside the door for an instant
and hastily retreat as though she had forgotten some important
part of her toilet. At nine she came to the doonvay again and
took a survey of the world, turning her head this way and that
with an air of elegant leisure. There she stood in placid en-
joyment of the morning scene for just half an hour, when she
came outside. Fearing to let her go, lest she might not return,
we caught her and at once excavated the nest. This consisted
of a tortuous passage three and a half inches long, which ended
in a pocket. It contained eighteen small beetles, all of which
were stiff and dead excepting two. These two were doubtful,
since although they gave no response to stimulation, even with
alcohol, they were flexible and had a general appearance of life.
Three days later these too were stiff.

These observations were made on the twenty-eighth and
twenty-ninth of August.

Philanfhiis punctatus Say.
Plate I., fig. 3.
This is a pretty little yellow banded species much resembling
Cerceris in appearance. The nest consists of a main gallery
with pockets leading from' it, each pocket being stored with one
egg and enough bees to nourish a single larva. When the wasps
emerge from the cocoon they find themselves in the company
of their nearest relatives and in possession of a dwelling place,
and they all live together for a time before starting out inde-
pendently to seek their own fortunes. On the fifth of August
we discovered on the island a happy family of this kind, consist-

118 THE SOLITARY WASPS.

ing of three brothers arid four sisters, the females, with their
bright yellow faces and mandibles, being handsomer than the
males. They seemed to be on the most :.micable terms with
each other, their only trouble being that while they were all
fond of looking out, the doorway was only large enough to hold
one at a time. The nest was opened in the morning at about
nine o'clock and during the next thirty or forty minutes their
comical little faces would appear, one after another, each wasp
enjoying the view for a few minutes with many twitchings of
the head, and then retreating to make way for another, perhaps
in response to some hint from behind. Then one by one they
would come out, circle about the spot and depart, sometimes
leaving one of their number tx> keep house all day alone. They
usually left the hole open but if there was a wasp within, it was
soon closed from below. During this playtime period they did
not return until they were ready to settl* down for the night,
the first one coming home at half after two or three o'clock and
the others arriving at intervals, none of them staying out later
than five. Most commonly they found the right spot without
trouble, scratched open the hole and then either closed it be-
hind them or stood waiting in the doorway for the next arrival.
Occasionally they had difiiculty in; locating the nest and worked
at two or three different places before finding it.

We, kept these wasps under close observation, often watching
the nest from the moment it was opened in the morning until
it was closed at night. On the twelfth of August, a week from
the time that we first saw them, one of the females felt the re-
sponsibilities of life settling down upon her. At half after four
in the afternoon she began to enlarge the nest and worked with a
great deal of energy for forty minutes. After a long disappear-
ance within the hole she would come up* backwards, kicking be-
hind her a quantity of earth which was not only taken outside
but was then spread out far and wide. She worked with the
front pair of legs which were curved inward, after the manner
of Bcmlex, and when a pebble or some such object came in her
way she either dragged it to a distance with her mandibles or

SOME GBA VE DIGGERS. 119

pushed it before her with her head in a T:ay quite peculiar t:>
herself. In distributing the earth that was taken out, she went
five and one-half inche? from the nest — a distance which is much
greater than is common among wasps, but which accords well
with the habits of pimctatus, since she continues the work of
excavation from day to day.

On August thirteenth, at half after eight in the morning, we
found that a second female, perhaps inspired by the example of
her sister, had made a new nest within two inches of the first one,
and had flown away, leaving it open. Presc ntly the other wasps
began to appear, one after the other, in their doorway. Two
of the males flew away and one of the females, doubtless the one
that we had seen digging the night before, began to work afresh
at making the nest larger. Probably she was excavating a
pocket for the reception of an egg, and the amount of labor re-
quired was enormously increased by the great length (about
twenty-two inches), of the main gallery by which the displaced
earth must be carried out. She worked for an hour and in
spreading the dirt about, inadvertently filled in the opening of
the second nest. At length she flew away.

At ten o'clock a female arrived carrying a bee of the species
Halictiis disparalis Cr., and tried to find nest Xo. 2. She
came to the wrong place and worked about, here and there, for
some minutes, holding the bee under the thorax,, clasped by the
second pair of legs. Being unsuccessful she dropped her bur-
den and fiew away for a few minutes. While she was gone we
removed a leaf that had fallen over her nest, and on her return
she at once descended upon the right spot and began to scratch
open the entrance, the bee being kicked backward with the re-
jected earth. When the way was clear, however, she picked it
up, brought it toward the hole, dropped it, ran in and out,
brought it nearer, ran in again and turning around in the tunnel
seized the bee in her mandibles and pulled it down. This per-
formance was due to the accidental obstruction of the gallery,
for we afterward found that punctatiis ordinarily files directly
into her nest, or, when it is closed, pauses en the wing to scratch

120 THE SOLITARY WASPS.

an opening witli the first legs. The bee is pushed backward a
little as she goes in but does not often project from under her
abdomen.

At fifteen minutes after ten the worker from nest ISTo. 1
brought in a bee, and from that time the two worked indus-
triously. Thej showed some individuality in their ways, for
!N^o. 2 always closed her door when she went away and never
circled at all, while Ko. 1 invariably circled before leaving and
always left her nest open. To be sure, there was a female left
on guard, so that perhaps she did not feel the need of caution.

Our wasps had not far to go for their victims. Forty feet
away,^ on the eastera side of the island, was a steep declivity,
and here, in the soft crumbly soil, was a great Halictus settle-
ment. 'No prettier sight can be imagined than is presented by
this colony on every sunny summer day. The whole bank is
riddled with nests and at the entrance of each stands a male bee,
his tiny head exactly filling the opening. The females are con-
stantly arriving, laden with pollen, whereupon the males po-
litely back inward to make way for them. Into this scene of
contented industry descends the ravaging PhilantJnis, taking
males and females alike.

On the afternoon of the fourteenth, of August our two work-
ers were in the full tide of affairs. No. 1 took in eleven bees
within two hours, but her record was somewhat confused as two
other females were going in and out at the same time. We felt
sure that neither of these was hunting, but one of them shared
in the labor of, the nest by helping with the work of excavation.

No. 2, however, was alone, so that we could keep a definite
account of her comings and goings. Her record is as follows:

Left. Returned. Left. Returned.

1.48 2.07 3.38 3.55

2.08 2.11 • 3.56 4.03

2.12 2.19 4.04 4.22

2.20 2.30 4.23 4.25

2.31 2.37 4.26 4.55

2.38 3.07 4.56 4.57

3.08 3.28 4.58 5.20

SOME GEA VE DIGGERS. 121

At this last return she brought in no load and at once closed
the nest for the night, after having stored thirteen bees in three
hours and nine minutes. It will be noticed that in some cases
thei capture of the bee occupied only one, two, or three minutes,
while at other times she was gone much longer. At each return
she stayed only an instant — just long enough to deposit the bee —
inside the nest, the minute that elapsed before she flew away be-
ing occupied in carefully closing the hole. The wasps that were
going in and out of nest Xo. 1 sometimes closed it when they
went away, but this was done in an untidy fashion, quite differ-
ent from the nicety and precision of jSTo. 2.

xVt half after five o'clock the) wasp that had been digging for
some little time at nest ISTo. 1, flew to nest iSTo. 2, opened it, and
attempted to enter, but was quickly driven out by the owner.
She then dug a little in several other places, finally returning
to sleep in the family home. On the next day we found that
No. 2 was tolerating in her nest one of the females that had not
yet begun to hunt, but whether it was the one she had rejected
the night before or the fourth member of the sisterhood we could
not tell. On the eighteenth, thi-ee days later, the wasp had left
this temporary home and made a nest for herself four feet away
•on the hillside. The males were still living in the first nest
with two females.

When the weather was cold and cloudy pu net at us remained
closely housed within the nest, or, at most, came out to do an
hour's digging and then again disappeared. The warmer the
weather and the more brilliant the sunshine the more rapidly
they worked. When leaving the nest they would often creep
out and walk around it three or four times before rising on their
wings, and even then would sometimes alight once or twice be-
fore flying away. The males, especially, liked to stand about
for a time, watching their more industrious sisters at their work.
The females usually began the day with digging, and frequently
closed it, toward night, in the same way.

In order to see the method of stinging we at one time provided
ourselves with a number of bees, and putting one of them into

122 THE SOLITARY WASPS.

a bottle, introduced a wasp. She seized it almost immediately^
with great vigor, and stung it once, under the neck, and then
dragged it up and down the bottle by one antenna which was
held in the mandibles. After a moment she shifted it and held
it with the second legs in the usual way. We now put in an-
other bee which she also caught, stung in the same place, and
then dropped without relaxing her hold of the first one. As she
seemed to have nothing further to show us we released her, and
after circling a little she took into her nest the bee that she was
carrying.

In our next experiment we used a larger glass, thinking that
with more space we might see malaxation. The instant that
the wasp was introduced she grasped the bee with one rapid
powerful motion, and stung it just under the neck as before.
Then holding it with the second legs she began to fly about in
the glass. We now introduced another bee, whereupon the first
one was relinquished, and the second was treated in exactly the
same way. The stinging was the beginning and the end of the
operation, and when we released her she at once took the bee
into the nest. There was no malaxation outside and certainly
there was none within, as was shown by the rapidity with which
the wasps issued from the nest after storing the bees. We
were only successful in getting the wasps to sting w^hen we tried
the experiment with those that were hunting. When those
that had not yet begun to store their nests w^ere put into the glass
they paid no attention to the bees.

The victim of the sting of punctatus is killed at once. Life is
extinct from the instant that the stroke is given. This is true
also of the honey-bee that is the victim of Fabre's Philanthus
apivorus, but the explanation that he gives of the action of his
wasp in thus dealing sudden death instead of paralysing its foe —
that the honey must be sucked out of the bee before it can be
safely used as food for the larva — does not hold good in our
case, since the honey that Ealictus carries to mix with the pollen
upon which her offspring are fed, is not removed.

As time went on we found on the island two other Philanthus-

SOME GRA VE DIGGERS. 12S

colonies, although that is rather too large a word to apply to
them, since one consisted of four nests and the other of only two.
When we came to excavate the nests of this species we were
greatly astonished at the length of the gallery, and not until
then did we properly appreciate the industry of these little wasps.
It is no small undertaking to follow one of their tunnels for
twenty-two inches, even when, as in this case, the greater part
of it is parallel to the surface of the ground. (PI. XI., fig. 2.)
We did not find distinct pockets, as the soil was very crumbly
and fell in as we worked, but we came upon clumps of bees an
inch or so to one side of the gallery and about three inches apart,
with larvae in different stages of development. In one nest we
found twenty-six bees in two clumps, some of them half-eaten
and some of them fresh, but all quite dead. We have no doubt
that punctatns completely provisions one pocket and closes the
opening from it into the gallery, before she starts another, mak-
ing a series of six or eight independent cells. The provision
for one lar^^a is probably twelve or fourteen bees, the capture
of which, in good weather, would be a fair day's work.

That the males do not always stay on in their ancestral home
is shown by an observation that we made on the only oc<?asion
that we ever saw tliis species in our garden. Nothing was stir-
ring at half past three o'clock in the afternoon and we had given
up work and started for home, when, in going up an inclined
part of the field, we noticed something in motion within a ragged-
edged hole which ran obliquely into the gi'ound. It seemed
strange that a wasp should be beginning its nest at so late an
hour, but a wasp it was, as we could plainly see when we took
an attitude sufficiently humble. It was loosening the earth with
its mandibles and then pushing it backward with its hind legs
and abdomen. We had scarcely settled down to watching it
when a second one of the same species appeared, and with a
good deal of fuss and flutter began to dig its hole close by. The
spot chosen by this second one proved unsatisfactory and another
beginning was made in a new place. Again something was
wrong, nor was a third choice any better. At last, however, the
work was started in earnest and might have been carried to a

124 THE SOLITARY WASPS.

conclusion if we had not cauglit the little creature to satisfy a
suspicion that had been growing in our minds. Yes, we were
right. The worker was not a female making a nest for the
rearing of her young, but a male pimctatus, preparing a shelter
for the night.

In the meantime the first wasp had pushed back such a quan-
tity of earth that the hole was entirely closed, but every few
minutes he came backing out to clear the way. At the end of
half an hour all became quiet. The door remained closed, and
doubtless the wasp was fast asleep. Putting a blade of grass
and then an inverted tumbler over the nest we left him for the
night.

On removing the glass at half past seven the next morning
we found the nest) open but the wasp not visible. At half past
eight the head appeared just inside the hole, the long anteniite
twitching now to this side, now to that, as if an inspection were
being made. Soon the head came out. The wasp stood for
some minutes making a survey, looking to right and left with
lively jerks of the body. Then, apparently concluding that the
day was not far enough advanced, he came out, whirled around,
and ran head-first into the nest. He probably took another
nap, for all was quiet until just before ten o'clock when the
antennae appeared again. The survey was taken asi before, first
from within and then with the head in view. At last he flew
out and making three circles, each one wider than the last, about
the place, flew away. He staid out all day and had not returned
at half past three in the afternoon, but on going down at half
past four we found that he had gone in and closed the door
from below.

It is clear, then, that these males do not construct a new lodg-
ing every night but return to the same spot to sleep. Other
wasps creep into crevices. We have often found them, in the
morning, in the holes of the posts of our cottage porch; but we
are glad to be able to put it down to the credit of one male that
he had sufficient foresight and industry to pro^ade a sleeping
place, and sufiicient intelligence to return to the spot when the
declining sun warns him that evening is approaching.

THE SPIDER RA VISHERS. 12&

CHAPTEK XII.

THE SPIDER RAVISHERS.

Pompiliis and Agenia.

Plates I., figs. 1, 2 and 7; v.; X., figs. 6, 7 and 8; XII., fig. 5;

XIII., fig. 1.

While Ammophila feeds her larva upon catei'pillars, and
Bemhear, after the manner of the social wasps, feeds her young
from day to day on dead flies, the Pompilidae, so far as their
hahits are known, all prey upon spiders. The family is a large
one in the United States, one hundred and twenty-seven species
having been described. The members of the group differ in
size, color, and habits, and the individuals of the same species
show the very considerable amount of variation which seems
common to all those groups of animals which have been care-
fully studied. Happily the old notion that habits and instincts,
unlike structural peculiarities, are always uniform, is no longer
insisted upon, and there is ample evidence for the opinion that
functional variations are as common as morphological. We
have studied five species of this family and have found their re-
spective roles of great interest.

According to Pabre the Prehch members of this genus, al-
though they do not make their own nests, still exercise some
foresight in the matter by selecting a suitable crevice before
catching their prey. Among the species that we have studied
qumquenotatus, Mguttatns, fuscipennis, marginatus, and in-'
term phis first catch the spider and then make the nest; while
calipterus and scelestiis prepare the nest before capturing their
prey.

126 THE SOLITARY WASPS.

Pompilus quinquenotatus Say.

Plate II., fig. 7; PL X., figs. 6, Y, 8.

This wasp is usually rather less than half an inch in length
and is black, the abdomen having a variable number of white
bands and a white tip.

It was on the last day of July that, ao we were walking
through the bean field, we saw a cloud of fine dust which came
spurting up out of the gi'ound like water in a fountain. By
watching intently we saw that the cause of the commotion was
the rapid action of the legs of some little creature that was al-
most hidden in the earth, and this proved to be our first example
of P. quinquenotatus.

She was working away as furiously as though she had studied
the poets and knew her carpe diem by heart. Paster and faster
went the slender little leg-s, higher and higher rose the jet of
dust above her. Then suddenly there was a pause. The bur-
rower had met with some obstacle. A moment more and she
came backing out of tl:3 hole, her feet slipping on. its crumbling
edges. In her mandibles she carried a pebble which was taken
to a distance of four or five inches. Then, moving quickly, she
swept away the dust that had accumulated near the mouth of
the nest, re-entered the hole, and resumed the labor of excava-
tion.

We thought that the rate at which she worked was too violent
to be kept up very long, and sure enough, before ten minutes
had passed the nest was deep enough for her piu-poses, and we
afterward learned to our chagrin, that it was too deep for ours.
The wasp came out, circled round the spot three or four times,
and then flew off like a hurricane. Never have we seen a crea-
ture so fiery, tempestuous, cyclonic. Before we knew her
proper title we took to "calling her the Tornado Wasp, and by
that name we shall always think of her.

Her flight was too rapid to follow but in a minute we saw her
returning. She was carrying a spider, a good sized specimen of
Epeira striw, which she had evidently deposited somewhere in

THE SPIDER BA VISHEBS. 127

the neigliborkcKxi before beginning to dig. Alighting near by
sbe left tbe spider lying on the ground while she ran to her nest
and kicked out a little more earth.. Then seizing it by one leg
she dragged it, going backward herself, into the nest. She re-
mained hidden for about two minutes, then reappeared, and,
seeming to be in as great a hurry as ever, filled the hole with
dirt. To disguise the spot and render it indistingiiishable from
the rest of the field was her next care. Hither and thither she
rushed, now bringing little pellets of earth and placing them
above the nest, now sweeping away the loose dust which might
suggest the presence of the crclie, and now tugging frantically
at a stone which she wanted to place over the hidden treasure,
but which was too deeply embedded in the earth to yield to her
efforts. She did her work faithfully although with such eager
haste that all was completed at the end of twenty minutes from
the time we saw her first. So well was the place hidden that it
was only by careful orientation that we could be certain of its
exact locality.

Her task accomplished, away flew our little tornado as though
she were pursued by the avenging spirits of all the spiders that
she had murdered, although more probably she was off in quest
of another of those meek and helpless victims.

"]!^ow," we said, "we will trace out the nest and make a draw-
ing of it. We will take the spider home and note its condition
from day to day, watching, at the same time the development of
the larva."

Enjoying this little aii--castle we began to excavate. Having
had experience with the nests of Ammopliila and Diodontus,
and knowing that the task might not be so' easy as it looked, we
went to work with all possible care. It seemed however that
some magician's trick — some deception of the senses — had been
played upon us. We saw the spider inten-ed, we at once dug up
the place and found nothing. Slowly and carefully we en-
larged our circle. We went down deeper until the opening was
large enough to liold a thousand spiders, — still nothing. Then
we tried another plan. Gathering all the earth that we had

128 THE SOLITARY WASP.

taken out we sifted it through our hands — in vain. At last we
acknowledged ourselves beaten, and trudged home empty-
handed.

Our pride was destined to be still further humbled. Three
times within that same week we saw the Tornado Wasp bury
her spider, and three times we failed, just as incredibly, to find
it. On the last of these occasions we did not let her fill the nest,
attempting to follow the tunnel and get out the spider as soon
as the egg was laid, but the lose unstable character of the soil
defeated us.

Our fifth example, however, dug her nest, not among the
beans but lower down in the potato field, where the ground was
firmer, and here we made our first successful excavation, — suc-
cessful only up to a certain point, since in getting out the spider
we dislodged the egg, and although it was at once replaced it
never developed. The spider was placed three inches below
the surface but we could not trace the tunnel. At our next
opportunity, wishing to make good this f ailiTre, we placed a
blade of grass in the opening just after the wasp began to fill it.
On being disturbed she assumed the most comically threatening
aspect, Avhirling around, lifting her wings, and then circling
about us. As soon as we moved back she dashed at the grass-
blade and pulled it out with great energy. A few minutes later
we made a similar att-empt and again she frustrated our plan,
but when we inserted the grass-blade for the third time, the
nest being now half filled, she let it remain. Some hours later,
with this to guide us, we succeeded in tracing the nest, but
much to our disappointment found it transformed into a ban-
queting hall. Scores of tiny red ants had discovered this rich
store of food. They had eaten the egg and were rapidly finish-
ing the spider.

Tvace afterward, in opening these nests, we found the same
ants in possession before us. It is probable that they are a
formidable enemy to this and other species of Pompilits, but
they seem to find the spider by burrowing beneath the surface,

THE SPIDER BA VISITERS. 129

SO that the elaborate hiding of the nest from above cannot be
meant as a protection against them.

Pompilus quinquenotatus has a decided preference as to the
spider that she takes. While Pelopaeus and Trypoxylon are en-
tirly indifferent both as to size and species, and the more nearly
related Pompilus marginatus takes ThomisMS, Drassus, At-
tus, Agalena or Lycosa, this more fastidious wa^p will not be
tempted from the spider of her choice. In more than fifty ex-
amples the victim in the play was invariably Epeira strix. If
she must confine herself to one species she has made a fortunate
selection, since there is no other spider so common in our neigh-
borhood, not only in the woods, but around the bams, and out-
buildings. Most frequently it was the female that was taken,
but tliis does not imply a preference for that sex, since the fe-
males are more abundant than the males. We have never seen
the spider captured and do not know where the sting is given,
but certainly this wasp woimds her prey very severely. The
epiders that we took from her were either dead or so completely
paralyzed that it required gTeat care and the use of a magni-
fying glass to determine that they were alive.

The next stage of her proceedings we are familiar with, as
we have frequently seen the wasp carry the spider. Unlike
her sister, marginatus, she usually flies with it, and seems not
at all encumbered by its weight. In many cases, however, she
drags it, holding it by one leg and running rapidly backward.

A suitable place for the nest being found the spider is very
prettily taken care of while the work is in progress. A plant,
■usually a bean or a sorrel, is chosen, and the strijp is hung in
the crotch of a branching stem, where it will be safe from the
<iepredations of ants. (Plate X., fig. 8.) This precaution is
not always taken. We have many times seen the spider left
on the ground, although there were plenty of plants at hand.

The next point is to decide upon the precise spot for the nest,
and here our wasp shows herself very uncertain and hard to
please. Xever have we seen one settle down and complete her
work in the spot first chosen. She dashes at a place and

130 THE SOLITARY WASPS.

scratches and digs away with furious energy for a few minuteSy.
and then starting up, she darts wildly hither and thither until
a new place, near by, is fixed upon and another beginning made.
In one instance eight different nests were started and some of
them half made, the little worker seeming to be beside herself
with excitement. After the decision is finally made the tun-
nelling is a rapid process. In one case it took the wasp a
whole hour to complete the work, but out of the thirty nests
that we saw made, nineteen were finished in from twenty to
twenty-five, minuter. Like Fabre's Spheco the wasp interrupts
herself three or four times to ^asit her spider and make sure-
that it is safe. When all is done she brings the stri^ to ^vithin
a foot or two of the opening, runs to the nest to take a final
look, and then, going backward herself, pulls it inside. In two
instances we saw the fidgety little creature go through a most
comical performance, which again recalls the Spliex of Fabre.
Leaving her treasure on the ground she ran to the nest and
kicked out a little more earth ; hastening back she dragged it an
inch nearer; then away she went to the nest again for more-
digging, and so on, dropping her spider half a dozen times
before she at last brought it home. In two other cases in which
there was no such anxiety about the size of the nest, there
was, in reality, more reason for it. Indeed in one instance the-
opening had to be enlarged before the spider could be taken in.

The laying of the egg takes only two or three minutes and
then the hole is filled up. In this part of her work quinquc-
notatus shows a great deal of variation, sometimes coming out
of the hole and sweeping in the dirt with her firet legs and'
sometimes standing in the tunnel while she draws the earth in
with her mandibles and then jams it down with the end of her
abdomen. The former plan was in vogue in the gai-den while
the latter was more common with the wasps on the island.
After the hole is filled the spot is covered with pellets of earth
and pebbles brought from a little distance, very much as is
done by AmmopJiila.

When we found that quinqiienotatus was a very common-

THE SPIDER RA VISITERS. 131

epecies, and that nearly every day brouglit us a fresh example,
we thought that we had the question of its stinging habits in
our own hands. What could be easier than to c^rry a striiv
about with us and to exchange it, when opportunity offered,
for the paralyzed spider of the wasp? The good results ob-
tained by Fabre and Marchal from this manceuvre made us con-
fident of success. We did not doubt that when the wasp came
for her spider and found it livelier than it ought to be, she
would repeat the stinging operation before our eyes.

Accordingly, the next time that we saw quinquenotatus dig-
ging we made a diligent search for her spider and soon found
it on a bean plant five feet away. Just as we discovered it,
however, the wasp swooped down and carried it to some purs-
lane, close to the hole, where she hung it up again, while she
went to make her final preparations at the nest. We seized
our chance and quickly substituted a fresh stride for the one
that had been paralyzed. Acording to the habit of its species
when danger threatens, it kept perfectly quiet, and when the
wasp returned it was hanging there as motionless as a piece of
dead matter. How she knew the difference was a mystery, but
she would not touch it. She seemed to think that she bad made
a mistake in the locality and that her own spider must be hang-
ing somewhere close by, for she hunted all over that plant and
then over several others near to it, returning continually to look
again in the right spot. After five minutes she gave it up, cir-
cled about thi-ee or four times, and flew off in the direction of
the woods to oat-ch another spider. Why did she go to the
woods? When she realized that the stria^ she had stung was
gone and that she must have another, why did she not take the
one that hung there in plain view? Our failure could not have
been due to the fact that we had handled the spider, since when,
on other occasions, we took one that had been paralyzed, exam-
ined it and then returned it to the wasp, she accepted it without
hesitation.

Disappointed though we were at the irrational conduct of our
wasp, we resolved to await her return and to try again. In

132 THE SOLITARY WASPS.

forty minutes she came back with another spider, but instead
of taking it into the nest she hung it upon a bean plant near bj
(Plate X., fig. Y), and then proceeded to dig a new hole a few
inches distant from the first. Foolish little wasp, what a waste
■of labor! Truly, if you are endowed with energy beyond your
fellows you are but meagerly furnished with reason.

Again we availed ourselves of our opportunity and substituted
our spider for hers. This time it had grown weary of playing
its motionless role and frequent readjustments were necessary
in order to keep it in position. At the moment that the wasp
came back to take it the spider scrambled from its place and be-
gan to make its way along the stem. The wasp evidently saw
it for she hovered over it a moment. She then flew to the next
plant where she hunted about over the leaves and branches in
search of her lost treasure. After a time she returned. The
spider had now come to a standstill and the wasp examined it
attentively, although without touching it. She then flew away
without circling at all, which might, perhaps, be taken as an in-
dication that she had no intention of returning to a place where
she had fared so badly.

Just at this moment we chanced to see another paralyzed strlv
hanging near by. Again the exchange of our specimen was ac-
complished, but when the second wasp came to find her spider
she gave us no more satisfaction than the first. The substitute
hung there quietly enough. "We ourselves could not have dis-
tinguished it from the original,, but quinquenotatus took a good
look at it, decided that something was wrong, hunted about a
little for her own spider and then flew away.

We had then, as the fruit of our morning's work, gained noth-
ing in regard to a knowledge of the stinging habits of our wasp,
but at least we had secured tliree freshly paralyzed spiders to
add to our laboratory collection. As to the striw that had so
kindly assisted us in our experiments, we placed it on a bush in
the pleasantest and most secluded corner of the garden and left
it there, wishing it a long and happy life.

THE SPIDER RAVISHERS. 133

Later on in the season we tried tlie same experiment. Taking
her spider from quinqnenotatus as she was dragging it to her
nest, we offered her a very lively striw in its place. She would
not notice it at all, and soon flew away. Half an hour later she
reappeared and seemed to be looking for a place to dig. As she
ran about on the ground we offered her another spider, dropping
it on the ground in front of her. This one behaved admirably,
drawing up its legs and keeping perfectly still, not moving even
when she felt of it and turned it over, but it was left without
any display of interest or emotion.

One day we saw a qmnqtienotatus finish her nest and go after
her spider. She was absent for some time and when an ant
passed by dragging a paralyzed stride that had evidently been
stolen from some wasp we thought that the one we were watch-
ing had been robbed, and rescuing the spider, placed it in the
doorway of the nest. We had judged wrongly, for a moment
later our wasp came back bringing her own spider, and dropping
it near by, ran to look at her nest. She was disturbed at finding
the way blocked, and dug out a little earth to one side of the
strix. Then she flew to some holes in the gTound not far away
and dug a little, first in one and then in the other. After this
she took a look at her spider and then went back and dug a
little more at her own nest. Finally she seized the impeding
strix by a leg and dragged it out of the way and paid no further
attention to it, storing her own spider and then flying away,
although the one she had rejected might have saved a hunting
expedition .

At another time we saw two wasps digging their nests two or
three feet apart. One of them finished before the other and
being unable to find her own spider (probably it had been car-
ried away by the ants), she seized that of her neighbor and bore
it away. The rightful owner saw, from a distance, what was
happening and ran to the rescue. A violent scrimmage en-
sued, the two wasps clinching and rolling over and over together.
The robber escaped and made off but was followed and caught

134 THE SOLITARY WASPS.

again. She fought so well for her ill-gotten treasure, however,
that she finally conquered the other and hunied off with her
prize. She showed by her manner that she felt the need of
haste, for instead of laying the spider down and looking at the
nest, she dragged it directly in, as though she feared another at-
tack. This was the first time that we had ever seen these wasps
fighting over their prey and we were surprised to find that they
would take spiders which they had not captured themselves,
since when we had tried to exchange with them they . had re-
fused to carry out our scheme. This was clearly an intelligent
(immoral?) act and could not be an affair of instinct.

Once again we witnessed a similar struggle. One of these
wasps was laboriously dragging her strir up a steep hillside
when a much bigger one of the same species descended upon
her and seized the spider. She was loth to give it up and they
both pulled until it seemed as though the poor creature would
be dismembered. The highway robber came off victorious and
after flying to a distance hung the spider up while she finished
a partly made nest, and then stored it away. It may be said in
extenuation of her conduct that since she had a nest started she
had probably been robbed herself, and therefore felt that she
was entitled to a spider.

The nests of quinquenotatus vary considerably according to
the kind of soil in which they are made, the firm clay of the gar-
den gi\^ng a result quite different from the fine diy earth of the
island, in which they are usually much larger and scarcely to be
distinguished from the holes of Benibex spinolae. In both lo-
calities, however, the nest consisted of a short tunnel, running
obliquely downward, with a slight enlargement at the end, but
with no change in the direction of the gallery. (Plate X.,
fig. 6.)

In the loose sand of a steep hillside we found that the wasps
had a different method. Their tunnels in this place, filled up
nearly as fast as they could dig them, and when they had
reached a depth of half an inch they turned off at a right angle,

THE SPIDEB RAVISHERS. 135

and excavated in an entirely new direction. They probably
derived some advant-age from this variation for we saw four in
succession follow the same plan, which certainly appeared to be
an intelligent adaptation of means to ends.

We once saw a wasp of this species digging her nest on the
Bembex field. When finished it was a large hole which could
not have been distinguished from those' of spinolae, which were
open all about, for the weather was bright and sunny. She
went away and soon reappeared with her spider, which was
dropped three feet away while she ran to make sure that all was
right, and now followed something that we had never seen be-
fore — she could not find her nest. She flew, she ran, she scur-
ried here and there, but she had utterly lost track of it. She
approached it several times, but there are no landmarks on the
Bembex field. We have often wondered how they find their
own places. After five minutes our wasp flew back to look it
her spider, and then returned to her search. She now began to
run into the Bemhex holes, but soon came out again even when
not chased out by the proprietor. Suddenly it seemed to strike
her that this was going to be a prolonged affair, and that her
treasure was exposed to danger, and hurrying back she dragged
it into the grass at the edge of the field, where it was hidden.
Again she resumed the hunt, flying wildly, now, all over the
field, running into wrong holes and even kicking out earth as
though she thought of appropriating them, but soon passing on.
Once more she became anxious about the spider, and canying it
up on to a plant suspended it there. Xow she seemed deter-
mined to take possession of eveiy hole that she went into, dig-
ging quite persistently in each, but ' then giving it up. One in
particular that was close by the spider, seemed to attract her and
she worked at it so long that we thought she had adopted it, for
it seemed to be unoccupied. At last, however, she made up
her mind that all further search was hopeless and that she had
better begin de novo, and forty minutes from the time that we
saw her first she started a new nest close to the spider, as though

136 THE SOLITARY WASPS.

she would run no more risks. This nest was successfully com-
pleted and the spider was stored away without further misad-
venture.

The egg of quinqucnotatvs can be but lightly attached to the
spider, for only once, out of many attempts, did we succeed in
getting it out without displacing it. In this case three days
elapsed before it hatched. The larva ate for a day or two but
then pined away and died. Another nest was opened on the
tenth day after the egg was laid, and in this the spider had
been entirely eaten and the lar\^a was justi spinning its cocoon^
so that the larval stage probably occupies about a week.

To show as accurately as possible the effect of the sting of
quinquenotatns upon her spider, we quote from our notes:

No. 32. August 6. We brought in three freshly paralyzed speci-
mens of E. strix taken from quiiiqiieuotatus before they were buried.
For purposes of comparison we killed another strix by compressing-
the head and thorax. We have numbered the spiders 1, 2, 3, and 4,
No. 4 being the one that we killed, and have placed them in separate
saucers. No. 1 is alive. Nos. 2 and 3 give no response to stimulation
and we believe them to be dead.

August 7. Nos. 1, 2, and 3 are all alive.

August 8. Nos. 1, 2, and 3 are alive and in good condition.

August 9. The three spiders are alive but look a little shrunken.
So far as we can see there is no difference between the abdomens of
those stung by the wasps and the one we killed; but the cephalo-
thorax of this last was a little broken and hence has become
shrunken.

August 11. Nos. 1 and 2 are still alive. No. 3 is dead and is evi-
dently decomposing, since the abdomen is soft and stays indented
when touched. This is also true of No. 4.

August 17. Nos. 1 and 2 are still alive.

August 19. The spiders are not only alive but are becoming more
active. "VMien touched, No. 1 raises the first pair of legs to the pos-
ture of attack or defence. It can almost turn itself over when placed
on its back. To move the saucer is a sufficient stimulation for this
one, but No. 2 does not respond unless touched. While No. 1 moves
the first pair of legs most readily, No. 2 moves the second pair more
than the first.

August 21. The two spiders seem to be regaining their health. No.
1 moves the body and all the legs without stimulation, and almost

THE SPIDER BAVISBERS. 137

turns itself Over. No. 2, when touched, moves first, second, and fourth,
pairs of legs.

August 22. Both spiders have lost power since yesterday. No. 1
moves only when touched. No. 2 scarcely responds at all, and has its
legs drawn up.

August 24. Both alive. No. 1 is better again — indeed very lively.
One touch makes it move the four anterior legs up and down twelve
or fifteen times, without stopping. No. 2 looks like a dead spider, but
when it is touched there is a feeble quivering of the legs.

August 29. No. 2 is dead. No. 1 is as lively as ever. When touched
it struggles for more than a minute. It can almost turn over.

September 2. The spider gains strength, and now moves its legs
without being stimulated.

September 6. The spider succeeds in turning over when placed on.
its back.

September 15. The spider is still in good condition.

No further record.

No. 43. August 8. Took strix from a nest of quinquenotatus. It is
barely alive.

August 10. When the spider is stimulated- the tip of the left an-
terior leg quivers a very little.

August 12. The spider is oead.

August 16. The body is beginning to soften and stays indented'
when touched.

August 19. Spider quite dry and hard.

No. 59. August 26. Took spider from wasp as she was dragging it
to her hole. It was plainly dead, the cephalothorax having been,
badly squeezed.

No. 52. August 16. Opened nest of quinqnenotatus and took out
the spider. We cannot determine whether it is dead. Under the
glass there seems to be a slight quivering of the legs.

August 17. The legs quiver.

August 26. There is still a slight quivering in response to stimula-
tion.

August 28. The spider is dead.

A summaiy of our notes shows a very wide variation in the
condition of the spiders. Out of eleven that were stung three
were killed at once, two lived four days, one five, one eleven,
one twenty-three, one twenty-five, one thirty-one, and one at
least forty days and probably longer.

/

138 THE SOLITARY WASPS.

Fabre bases his very strongest arguments for tke exactness of
tbe method by which wasps sting their victims^ upon the actions
of one of the Pompilidae* but certainly P. qidnquenotatus can
make no claim to nice workmanship, for if she occasionally
stings in such a way that life is preserved for some time it seems
to be a matter of chance rather than of skill. In one respect,
however, looking at the matter from Fabre's point of view, she
is very successful. Her victim is left so motionless as to be a per-
fectly safe repository for the egg. Even in the case of the
spider that lived forty days the power of motion did not return,
to any extent, during the first ten or twelve days, and before this
time in the natural course of events, there would have been noth-
ing left to move.

We look back with much pleasure upon our acquaintance
with this gay, excitable little wasp. She was so full of breezy
energy that it was always delightful to meet her, and she
showed so wide a variation in individual character that we sel-
dom watched her without learning something new.

Pompilus Hguttatus Fabr.

This wasp varies from one-quarter of an inch in length to
three times that size, and is marked with one or two interrupted
white bands on the abdomen. It is extremely common upon the
island in our lake, the males especially appearing in swarms
about the first of August, when they may be seen attempting to
mate not only with females of their own kind but also with
those of quinquenotatus, which is sometimes described as a vari-
ety of the same species. Their habits are certainly much alike
although quitiqitenotatus is distinctly the more excitable of the
two, and preys solely upon Epeira striae, while higuttatus is
occasionally seen with Epeira labyrintliea, a much less common
spider. One peculiarity- of higuttatus is her passion for wash-
ing herself. After she has caught her spider and bestowed it
safely, she flies to an adjoining plant and falls to brushing off her
wings and legs, and washing her face again and again, as though

*Souvenirs Entomologiques, Quatrieme Serie, p. 267.

THE SPIDER RA VISHERS. 139

she would never finisli. When at last she is satisfied with her-
self she searches for a nesting place, starting and abandoning a
number of holes before she settles down. After a little work
she becomes anxious about her spider and goes back to look at
it, but instead of going to the spot she usually flies to the place of
her washing operations, and hunts about for five or ten minutes
before she finds the right plant. Under like circumstances quin-
queuotatiis would be wild ^nth excitement and anxiety, but it
is not so with higuttatus — she is even calm enough to stop an<j
sip nectar from the flowers. After she has rediscovered her
treasure she does not leave it until she has circled about the
place to impress the surroundings upon her memory. As a re-
sult, when she next visits the spider she finds it without diffi-
culty. She often comes back to look at it four or five times be-
fore the nest is finished, the process taking anywhere from fif-
teen minutes to an hour. The tunnel runs in obliquely for an
inch or an inch and a half and ends in a slight enlargement.
The filling is sometimes done from within, the wasp standing in
the hole while she draws the earth in with her mandibles and
jams it down with her abdomen; and sometimes from without,
the earth being kicked in and the surface then smoothed over.
When we once inteniipted the process in order to dig on': the
spider, the courageous little wasp alighted upon the knife with
which we were working, in her eft'ort to protect her nest.

We have never seen higuttahis make a long flight while car-
rying her spider, as is commonly done by qmnquenotatus, her
most common habit being to run backward, dragging it by a
leg. In three instances that came under our notice the wasp
seemed resolved not to take one step on the ground, and made
her way along by climbing backward up on to some elevated
place and then flying forward in the direction that she wished
to pursue. These flights were short, covering only from two
to fourteen inches. As soon as she alighted she began to climb
again, perhaps only to the top of a stone or a lump of earth, if
nothing higher were at hand, but oftener scrambling up the
stem of some plant or blade of grass. This mode of progress

140 THE SOLITARY V/ASPS.

was not well adapted to getting across the onion field, and a
wasp looked very absurd trying to go backward up the slippery
stalks for five minutes at a time without making the slightest
advance. In other cases she kept patiently to her feet until
she came to a plant that was not only easy to climb, but higK
enough to give her a real advantage.

In taking the spider to its final resting place, higiittatus drops-
it once or twice by the wayside while she inspects the nest and
perhaps adds' a few finishing touches. At the last she backs in,
dragging it after her.

An egg that we took from a nest just after it was laid, was
fastened to the spider on the right side of the abdomen. It
hatched at the end of forty hours, and had a healthy larval life-
of eight days, spinning its cocoon on July twentieth. On the
fifteenth of August we found that it had flown.

Of three spiders stung by Mguiiatus, one was dead when
taken from the wasp. The second, taken on July sixth, seemed
to be quite dead until the eighth, when it gave a slight response-
to stimulation. From this time it improved, at first slowly and
then rapidly, until on July fifteenth it drank water and moved
all its legs without stimulation. On the eighteenth it began ta
walk, and by the sixth of September it had entirely regained its
health and was released. The third spider, which was taken
with the egg upon it, lived until it was destroyed by the larva.

PompilKS fnscipennis St. Fargeau.

PI. L, fig. 2; PL XII., fig. 5.

This species, which is a little smaller than P. quinquenotaus,
is black, with the red girdle that appears so frequently among
the solitary wasps. The first time that we ever saw this wasp
she was running rapidly backward over the bare ground, the
brilliant red of her body flashing in the sunlight as she dragged
along a little spider of the genus Thomisiis. Presently she
carried it up on to a leaf and began to bite at it, but being dis-
turbed by an ant, hurried on with a much agitated manner^

THE SPIDER RA VISITERS. 141

Soon she stopped again and resumed her attack, biting savagely
^t the legs near their junction with the body and now, looking
closely, we saw that two of them had been completely cut off.
While occupied in this way the wasp was evidently intensely ex-
•cited. She lay on one side with the abdomen bent under, turn-
ing the spider over and over as she worked. After a time she
carried it onward to the potato-field, where the plants afforded
some shelter, and placing it upon a leaf, well above the ground,
began to dig near by. She worked almost entirely with her
mandibles, lying sometimes on her side and sometimes on her
back as she cut away the earth, which was pushed out with the
end of her abdomen. When she had worked for ten minutes
and had gone in the length of her body, she picked up the spider
and made rapidly off with it, several times rising on her %\dngs
and flying backward for a few inches. A little further along
she again deposited it on a leaf and began to dig in a fresh place.
At the end of twenty minutes the nest was ready but in bring-
ing the spider she missed her direction and carried it to one side.
Dropping it on the ground she began to hunt about for her
hole, but was distracted with excitement and ran so far afield
that we feared she would never find it. At last, however, she
came to the place, ran in for a moment, brought the spider
nearer, dropped it and ran to the nest once more, caught it up
again, and tried to back in with it. She was holding it by the
under side of the body, the venter being toward the hole, and
the legs spread out and stopped its entrance. A moment's tug-
ging comdnced her that this would not do, and she then turned
the spider over, holding it by the back, whereupon the legs at
once folded themselves across the underside of the thorax and
the spider was drawn out of sight.

After the egg was laid the wasp came up to the edge of the
hole and drawing in some earth with her mandibles began to
dance up and down upon it, jamming it into place with her
abdomen. Afterguards she came up higher and drew the dirt
in with her first legs, not getting out of the hole until it was
entirely filled up. Then began a remarkable performance.

142 THE SOLITARY WASPS.

Bracing herself firmly on lier legs she used the end of her abdo-
men as an instrument and with it she now pounded the earth,
now ruhhed it, like a pestle in a mortar, and now used it as a
brush to sweep away loose dust. Sometimes she would throw
a little earth back under her body with her mandibles and rub
it down with her abdomen. This part of the work being fin-
ished she spent a few minutes in sweeping the ground with her
first legs, and then brought a quantity of small objects and
placed them over the nest, — a little stick, the petal of a faded
flower, a scrap of dead leaf, and so on, until ten or twelve things
had been collected. This artistic finishing up of her duties re-
called Ammophila, but among our subsequent examples of
fuscipennis we never saw one do her work with such nicety.
They were usually contented to fill in the nest more or less
compactly, sometimes doing much of the work from the outside,
to brush off the surface without any rubbing or pounding, and
then to bring two or three little pebbles or lumps of earth to
place over the spot.

So far as we were concerned this was one of the most fearless
of the wasps, not even interrupting her work when we once
placed a glass over her as she was filling her nest, but the ap-
proach of an ant would throw her into a perfect panic and
seizing her spider she would make off with every sign of terror.
It is difficut to understand why wasps of this species, as well
as of higvttatKS, never offer combat to the ants that rob them
right and left, but invariably seek safety in retreat.

P. fitscipennis rarely circles about when leaving a place, and
this is unfortunate since her sense of locality semes to be partic-
ularly weak. She nearly always has to hunt for the plant upon
which she has placed her spider, and always loses track of her
nest when she tries to bring the spider to it. (PL XII., fig. 5.)
We once caught her as she was canying her spider, and then re-
leased her on the same spot, but she became so much confused
that without our assistance she would never have found it again.

P. fuscipennis fastens, her egg to the abdomen of the spider.
An egg that was taken from the nest just after it was laid

THE SPIDER HA VISHERS. 143-

batclied at tlie end of forty-nine hours, but the larva died on the
following day, so that we have no record of this stage of its ex-
istence.

Of eight spiders taken from this wasp, two were dead and
the others were badly paralyzed, responding only to careful
stimulation. One of these improved after a time but the gain
was not permanent as it died on the ninth day.

One nest was made in a large lump of earth and ran in hor-
izontally; but all the others that we saw, went dowm almost
vertically.

Of ten spiders that we saw in the possession of fuscipennis,
nine belonged to a single species of the genus Tliomisus. The
tenth was a very small, immature, male Lycosid, and had been
captured by a tiny wasp of rather less than half the ordinary
size.

The most interesting thing about fuscipennis is her habit of
biting the legs of her victims. The instinct is very irregularly
developed since four out of ten spidei-s had not lost any legs,
while the others had been deprived of one or two. No one who
has watched the wasp can. doubt that the habit is related to the
fact that she makes a very small nest in comparison to the size
of her prey. The spider never went in easily, always requiring
to be shifted and turned and tugged at. There was an especial
tendency to bite at the legs at this point of time, when the wasp,
standing within the tunnel, was trying to drag the spider down.
In one instance she managed to get it past the entrance, but it
stuck in the gallery, and after working at it in that position for
a time she brought it out, subjected the legs to a severe squeez-
ing, and then tried again. It was still a very bad fit, but by
turning it about and pulling at it she succeeded in getting it
in. It may be that the object of biting the legs is not to re-
move them but to render them limber so that they will bend
easily. Whatever the process may be it is carried on at inter-
vals, from the time the spider is captured. As she carries it,
the wasp pauses again and again, now on bare ground, and now
in a sheltered place or on some plant to renew her efforts at'

144 THE SOLITARY WASPS.

getting the legs into a satisfactory state. The details of the
condition in which we found them may be interesting. Four
spiders retained their full complement of legs but in one of
these they had all been badly squeezed, the marks of the man-
dibles being plainly visible on the trochanters; one had lost the
three distal joints of the third leg on one side; one had lost a
leg of the third pair, and two others showed signs of having been
bitten; another had lost a leg of the first pair, another one of
the second, and still another, one of the fourth, while the most
seriously mutilated spider in the series had lost the third and
fourth legs on one side. P. fvscipenms was to be seen in our
garden from the twenty-first of July until we left the country
on September tenth.

Pompilus calipterus Say.

It was on the fifth of August that we saw this good sized,
dark gray wasp, walking up and down a fence post. A little
scrutiny showed that she was carrying pellets of earth from the
ground into a hole four feet above, in the wood, and very odd
she looked, making this journey again and again on foot instead
of using her wings. Upon cutting away the post we found that
she was just partitioning off the second apartment in what was
doubtless intended to be a long series. Both cells contained
female spiders of the species Xysticus ferox, that in the inner
one being twice as large as the other, and each spider had an
e^g on the side of the abdomen. The large one was dead, but
the other responded feebly to stimulation and lived in this
state for four days. One of the eggs, the one that had just
been laid when we opened the nest, hatched at the end of sixty
hours, but the lan^a did not live.

Pompilus marginatus^ Say.

Plate I., fig. 1.

Our acquaintance with this remarkable wasp began in the
middle of July. She is a small creature, only half an inch long,
and is dressed in black, with a bright orange spot on each side

THE SPIDER BA VISHERS. 145

of the anterior part of the abdomen. "We were watching the
pretty little Diodonti, as they filled their holes with aphides,
when we saw her going backward, dragging along a medium-
sized spider. Soon she came to an onion flower that was lying
on the ground. Here she stopped and, after a moment's hesita-
tion, drew her prey in among the blossoms of the cluster so that
it was hidden from view. It was not long before she came out
and began to fly about near the ground, frequently alighting to
poke her head into cracks and to run again and again into little
chance holes. IN^ever did an insect behave in a more demented
manner, and although there may have been a method in her
madness it was difficult to discover it. No hole nor cranny
pleased her and back she flew to the onion to see whether her
booty was safe. For fifteen minutes she ran and flew now
here, now there, hurry and anxiety in every movement, return-
ing frequently to reassure herself about the vSpider. Several
times she entered a hole at the base of a weed, not a made nest,
but an accidental crevice, and this spot was at length chosen
either as a temporary or a final resting place for her spider, since
she dragged it from the onion and deposited it here. We tried to
capture the wasp, but having failed in this, we dug out the
spider. It was three inches down, the hole being deeper than
it looked from the outside. There was no egg upon it. Evi-
dently the work had not been finished for the restless creature
returned fifteen times within an hour to the broken nest, either
for the purpose of laying her egg or to remove the spider to
another resting-place on her homeward way.

The spider, which was an Agalena naevia, about two-thirds
grown, was dead. We reached this conclusion only after most
careful investigation and are satisfied that there was no mistake.
We thought, though we may have been mistaken, that both
head and abdomen appeared slightly crushed. On the follow-
ing-day, July fourteenth, we re-examined it, and found the legs
drawn up to the body and quite stiff. In the next two days it
became dryer and somewhat shrunken, and by the eighteenth
it was quite dry. As late as the twenty-third, however, it was
10

146 THE SOLITARY WASPS.

in sufficiently good condition to have served as food for any of
the nurslings to which we havei played foster-mother.

This was our first specimen of marginatns, and a month,
passed before we met another. It was while watching some
Bembecidae that we saw the pretty little orange-spotted worker
dragging a small Thomisid across their nesting ground. The
spider was so small that she held it in her mandibles well above
the ground, and v/e only speak of her as dragging it because
she walked backward and acted as though she were obliged to
exert herself. Quite often the spiders taken by this species are
too large to be carried, and then it is necessary to drag them,
and this habit is so ingTained that when it would be much more
convenient to go straight ahead they stick to the ancient cus-
tom, and seem unable to move in any other way. This little
wasp was in a frantic hurry, running backward into the Benibex
holes and then scrambling out again until she had crossed the
field and had turned to one side, having gone, since we first saw
her, about fifteen feet. Here she dropped the spider and be-
gan to skim over the ground — it could not be called running
and yet it was not flying, — until she found a circular hole in
the black earth, which looked as if it ran vertically downward.
At the time we thought that this was a nest that she had made
for herself, but we afterward concluded that it had been ex-
cavated by some other creature, that she had found it and de-
termined to make use of it, and that she was bringing her prey
to the spot with that end in view. Without entering she rushed
back to the spider, but after carrying it a few inches, dropped it
and ran to take another look at the nest. By this time, how-
ever, she was too much excited to know what she was about,
and for five minutes she scurried over the ground without find-
ing it. During this time she picked up the spider four
times, carried it a little way and then dropped it. The last time
she carried it to the edge of the grass and stored it there, this
being her first attempt at concealment. She now found the
hole again and brought the spider nearly to it, but by this time
she was perfectly beside herself. The spider was seized again

THE SPIDER RA VI8HERS. 147

and again, only to be dropped tlie next second, wliile tlie wasp
rushed back and forth between it and the hole. In time this
method of procedure brought it close to the nest, but it was car-
ried around the edge once or twice even then. At last, acci-
dentally as it seemed, it fell in, when the wasp quickly ran in
also and pulled it down. Eor half an hour she remained inside
and when she came out we caught her to make sure of her iden-
tity. As we set her free immediately we expected her to go to
work at covering her nost, but in, this we were disappointed for
she did not return. We left the place undisturbed from the
thirteenth to the fifteenth of August, when we dug up the nest.
We found the spider, but if there was any egg upon it we lost
it. The spider was alive, as was shown by a quivering of the
legs. This quivering grew fainter and fainter until upon the
nineteenth it was scarcely perceptible, and on the twenty-first
the spider was^dead. Our first spider had been stung to death
at once, while this one lived seven days and a half after being
stored.

A third marginatus was discovered at noon of the nineteenth.
She had dragged her prey from a distance, frequently leaving
it to hunt about after the manner of her kind. We found no
egg on the spider — a Drassus — which was paralyzed, the an-
terior pair of legs quivering. On the morning of the twentieth
we felt sure that it was dead, still we re-examined it on the
twenty-first and twenty-second to be certain that there was no
recovery.

On August twenty-sixth we found a fourth specimen of
marginatus. She was running rapidly backwards dragging a
young Phidippus tripmictatus which she grasped in any way
that was convenient, sometimes one side being up and some-
times the other. When she reached the grass at one side of the
field she left the spider on the ground and began to hunt about
for a place in which to bestow it. About six feet away she dis-
covered a cavity made by the piling together of two or three
lumps of earth. This she examined carefully, first outside and
then within, going in by one opening and coming out by an.-

148 THE SOLITARY WASPS.

other. All seemed satisfactory for she went back for the spider
and after the usual amount of fluttering to and fro between it and
the hole, brought it into the hiding place. Then she came out
and began to hunt far and wide. All about the place she went,
over a circle of thirty feet in diameter, her manner bespeaking
the utmost anxiety and huny. Twice she visited her spider to
see if all were well. Finally, ten feet up the hillside, she ran
into an opening among some stones, staid a few minutes, hur-
ried down the hill and dragged the spider up toward this new
resting-place. On the way she dropped it and hunted around
in great agitation until she found it again. At last she disap-
peared with it under the stones. After watching the place for

Diagram of road over which a spider was carried by P. marainatvs.
The wasp was first seen at A ; B, C and D are the spots at which the
spider was hidden while she hunted about for a final resting place.

nearly an hour we went away for a time, confidently expecting
that when we returned we should find the spider with an egg
upon it, but we had been deceived. On our return the hole
was empty, and we concluded that it had been only another
resting-place, the third, on her homeward march. The dia-
gram of the road over which the spider was carried may aid in
giving an idea of her movements.

Our fifth specimen of marginahis had caught a small Thoni-
isid which she held in Jier mandibles entirely off the ground,
walking backwards, nevertheless, as if she were dragging it.
Unlike any of the others that we had seen, instead of hiding
the spider in a hole or under something on the ground, she car-
ried it up into a purslane plant and hung it there. After
some hunting she came back and carried it a little way, and

THE SPIDER BA VISHERS. 149

then, climbing a bean plant, deposited it upon a leaf whicli was
closely covered by another. Then she ran off again and was
gone thirty-five minutes. "We remained with the spider, since
the plants were so close together that it was impossible to fol-
low her. When she returned she seized her treasure and started
off among the plants where, in spite of our efforts to the con-
trary, we soon lost her. A sixth example added little to our
knowledge. She carried a small tripiinctatus in her mandibles
as she ran backward. She was as frantically anxious to ac-
complish something, and as helplessly incompetent to accom-
plish anything as the others. Once her victim was hung up on
a sorrel plant, and once it was hidden within a hole, where she
remained "s\dth it for some minutes. When she came out and
flew away we dug it out, but there was no egg upon it, so we had
taken it too soon. It was severely paralyzed so that for three
days there was scarcely any quivering in response to stimula-
tion. On the fourth day it was a little better, but on the sev-
enth, it died.

On September first, while out in the bean patch, we saw a
large Lycosid running madly, first in one direction and then in
another. Hovering eagerly and excitedly just above, was our
marginatifs, dashing down at the spider again and again as it
came into view for an instant, and then circling wildly around
until it appeared once more. ]^ow she pounced upon the fright-
ened spider but missed her aim, now she really grasped it but
was shaken off. At last the end came. The wasp descended
upon the doomed spider and there was a violent struggle, both
the combatants rolling over and over upon the ground, while all
that we could distinguish was the flashing of the red upon the
body of the wasp. In an instant it was over, and the wasp
rose, leaving the spider limp and motionless, upon its back.
In our other examples of marginatus the spider taken had been
so small that the wasp might easily have held it and thrust her
sting into any spot that she pleased, but this Lycosid was a dif-
ferent antagonist. In the fierce battle where the two were so
neai'ly matched, there could have been but slight opportunity

150 THE SOLITARY WASPS.

for skillful surgery. In point of strengtli the wasp was at a
disadvantage, and slie must have come off -vactor by the quick use
of her sting. Under these circumstances she must have struck
when and where she could, without any selection of a particular
spot. That she quite realized the power of her foe was shown
by her next action. With the utmost circumspection she set-
tled down upon the spider and made a prolonged and careful
examination of the mouth parts. The investigation was satis-
factory and without any further stinging she seized the spider
by one leg and, this time, really dragged it off. It was a good
load for her and it evidently required all of her strength to pull
it along. ISTot far away was a Imnp of earth and under this the
treasure was stowed and then began the usual hunting perform-
ance, which soon resulted in the discovery of another cavity
which had a very small opening. She crept in, remained a min-
ute, and then came out and brought her spider to this new
hiding place. The head went in easily but it took a gi^eat deal
of tugging to get the rest to follow. At last both spider and
wasp were out of sight and everything remained quiet for so
long that we began to think that this time we were really to see
the final act in the play. But no, when the little wasp came
creeping out it was only to start off on another extended tour
in which we did not attempt to follow her. She doubtless se-
lected another halting-place, for when she returned it was to try
to get the spider out of the hole by pulling at one of its hind
legs. The task, however, was not an easy one. She exerted
all her strength, so that we expected to see the poor victim dis-
membered before our eyes, and still it did not come. At last
she seemed to realize that there was more than one way to ac-
complish her end, and turned her attention to cutting away the
earth to make the opening larger. After a few moments' work
she tried again, and although the passage was still much too
small for convenience the spider was at length dragged forth,
looking much the worse for wear. As she moved away we
alarmed her by lifting some vines that prevented our keeping

THE SPIDER RA VIS HERS. 151

lier in \dew, and she flew up, leaving the spider on the ground.
We seized the opportunity to bend and twist the plants this
way and that so that the ground might be left uncovered. The
changes that we made probably disconcerted her for she seemed
to lose track of her prey. For over half an hour she hunted
about, circling above the place and running around and aroimd
over the ground. She often came so close to the spider that
we could not understand why she did not see it. At last it was
recovered and again she started off. We tried to follow her
but the vines were so thick that, in spite of our efforts, she
soon disappeared into the undiscovered country which we thus
far had been unable to penetrate.

Up to this time we had been entirely unable to understand
the actions of marginatus, and each new example added to our
confusion instead of clearing it away. We were inclined to
think that she never made a nest for herself but caught her
spider and then hun-ied about for a good place to store it, and
that her absurd conduct was the result of an indecision of char-
acter which made it extremely difficult for her to choose a place
and be contented with it. The last part of this judg-ment holds
true, even now when we know her whole history, but we have
at last learned that she does dig her own nest.

We had watched a wasp for some time as she can-ied her
spider from place to place, and finally saw her take it into a
crevice among some rough lumps of earth which she had pre-
viously examined. We expected one of the long spells of event-
less waiting to which she had accustomed us, but on lying down
and peering into the hole we found that there was an opening
on the further side, for a ray of light feebly penetrated the
interior. Moving about in this dim illumination was our wasp,
and after a little, we could see, quite distinctly, that she was
digging a hole. This then is her method — to find some sheltered
hiding-place where she may secretly make her nest, that no
creature may know where her treasure is hidden.

We have twice seen a marginatus pick up her spider and fly

152 THE SOLITARY WASPS.

■witli it backward for a long distance — as mucli as four or five
feet. This recalls the wasp which is said to fly backward before
a moving horse and catch the flies that are hovering over it .

P. marginatus is not troubled by any notion as to the family
connections of the spider that she takes. Anything will do
provided she is strong enough to overcome it and carry it to her
nest. The effect of her sting is quite variable since in some
cases the victim was killed at once while in others it was but
little affected in the beginning and lived for eighteen or twenty
days.

Although we have made observations upon thirteen individ-
uals of this species we have never succeeded in getting the spi-
der with the egg upon it.

Pmnpilus interruptus Say.

Early in the afternoon of the fifth of July, we saw this small,
yellow-banded wasp, flying slowly about from leaf to leaf and
from plant to plant, dropping to the gi'ound, now and then, to
run a little distance on the tips of her toes, in a peculiarly dainty
manner as though the ground were not good enough for her to
walk upon. She came back, again and again, to a spot under
a weed where there was a round shallow hole in the ground,
and presently she began, to work at this, showing that it was a
partly made nest. She carried the earth out in her mandibles
depositing it at the edge of the hole, and, after a little, pushed
away the accumulation with her feet. As she went deeper
the dirt was passed under her body and pushed up to the sur-
face with her legs. There was no kicking and all her motions
were slow. Every few minutes she flew up to a twig where
she stood very high on her legs, holding her wings up stiffly
at a right angle to her body. This manner of lifting the wings
was very peculiar, and gave her somewhat the look of the wasps
of the genus Yespa. When she had gone her own length into
the ground she came out and looked at her prey, a large Epeira
striw, which was hanging in the crotch of a weed close by.
After this she flew off toward the west and was gone five min-

THE SPIDER BAVISHERS. 153

utes, then came back and, taking a look at the spider, passed
on toward the east and began to run about on the ground as
though shei were looking for something. At length she started
a fresh nest, about eight feet from the first one. She dug slowly
but persistently, working more like fuscipennis than any other
of the Pompilidae, turning around and around in the timnel
so that her back was sometimes up ..nd sometimes down. As
a result of this method her hole was perfectly circular. After
twenty minutes, when she had gone in rather more than her
own length, she flevv to her spider, which she found without
any trouble, seized' it by one leg and ran rapidly backward with
it directly toward the nest. "When within ten inches she
dropped it and hurried on to see if everything were right, re-
turned, picked it up again, and carried it to within two inches,
where it was left while she took one more look. Everything
was in order, and seizing the spider she backed, in with it and
disappeared. After two minutes she came out and began to cut
away the earth near the entrance and to push it in, and then,
after a little, to fill the hole with the dirt that had been taken
out, which she pushed down with her legs. The whole opera-
tion occupied about forty-five minutes but before she was quite
done we caught her and opened the nest. This proved to be
only a little more than an inch deep with a slight enlargement
at the bottom. The spider was dead and exuded a fluid from
its mouth. The egg was placed on the right side of the ab-
domen, near the middle. Forty-eight hours later it looked as
if just ready to hatch but at this point it died.

Pompilus scelestus Cresson.

At eleven o'clock on the morning of a warm day in the mid-
dle of August we saw this steel-blue Pompilus dragging a big
Lycosid across a field. The spider was 16 mm. long and wide
in proportion while the wasp was but 13 mm. long and very
slender, so that the weight of the spider was at least three times
that of its captor. The necessity for going backward was evi-
dent in this case, but the wasp moved rapidly considering the-

154 THE SOLITARY WASPS.

load that she was dragging. As she worked her waj along she
made frequent pauses, stopping for two or three minutes at a
time in some little hollow, or under leaves or weeds. She spent
a good deal of time, during these pauses, in cleaning herself,
and a good deal of time also in doing something to the spider
which we could not understand. She seemed to be biting the
legs, near the body, beginning with an anterior leg on one side
and working backward and then repeating the operation on the
other side. She went through this squeezing process again and
again, and to us it looked as though she might be trying to
force back the juices from the legs into the body preparatory
to cutting them off, but after a time she would seize her prey
and start on again. She had made her way along in this fashion
for some ten feet, when a second wasp appeared and alighted on
a weed near by. This interloper was a trifle smaller than the
other, and from her actions was evidently greatly interested in
the paralyzed spider. When the Pompilus stopped for a mo-
ment the other moved from stem to stem in a stealthy manner
just as a cat stalks a bird. The rightful owner of the prey was
disturbed and dashed at the invader, driving her away again
and again, but she flew only a short distance and was soon back,
always creeping nearer and nearer to the spider. We, too, were
watching with closest attention, but our desire was to see the
speedy home-coming of Pompilus and to learn whether she cut
off the legs of her victim, and so, interesting as was the contest
between the wasp and the wasp-inquiline, we decided to interfere
and remove the intruder. This was very easily accomplished
since the little insect was so intent upon getting near to the
spider that she was oblivious to our presence and allowed us to
place a bottle over her as she stood eagerly looking for a chance
to advance. Her removal gave great relief to the other wasp
as was manifested by an entire change of manner. Before, she
had been constantly on the lookout, moving only with the
greatest circumspection, but now she relaxed her vigilance.
With the Cero pales in our vial we, too, felt relieved, and now
the path of discovery seemed clear before us, but scarcely had

THE SPIDER RA VISHERS. 155

things assumed their old status when a second enemy, a much
larger and bolder Ceropales, threw both the Pompilus and our-
selves into consternation. Again we took the side of our wasp
and drove the other one off, but only to see it return a few
moments later. The Pompilus now flew at it in a most gallant
fashion and pursued it far afield, but when she came back the
enemy was but a few seconds behind her. Here we again in-
terposed and removed the second Ceropales from the field of
action.

All cause for anxiety being over the wasp now resumed her
journey. Before long she came to a shallow depression in the
ground which was partly sheltered by an overhanging lump of
earth, and under this covering she dropped the spider and again
began to squeeze its legs. After a moment she removed it to
the other side of the depression, where it was subjected to fur-
ther manipulation. Xext, her toilet was attended to, and then
the spider was carried back and placed again under the lump of
earth. At least ten times was that limp and helpless creature
dragged from one side to the other of the little depression, a
distance of about two inches, the time between being filled in by
the wasp with cleaning herself and squeezing the legs of her vic-
tim. After forty minutes of this tedious delay the moment came
when she picked up her burden with renewed detennination
and started rapidly on her way. We kept very close to her
but she did not allow our presence to inteiTupt her work, and,
indeed, paid no attention to it. After she had gone along for
a distance of about eight feet there was another pause, of only
five minutes this time, and when she resumed her onward march
it was in a new direction. Thus far she had gone almost due
south but now she turned and went six feet toward the west.
Suddenly the spider was dropped. There was no hole in sight
but the wasp seemed to feel that some important crisis had ar-
rived. Her whole manner was excited and flurried and we
thought that surely we had reached the neighborhood of the
nest. How little we understood her! Her nest was still far
away, and it may be that she had just begun to realize that the

156 THE SOLITARY WASPS.

task slie had undertaken was too heavy for her accomplishment —
that at her present rate of progress her strength would be ex-
hausted before she could reach her goal. At any rate some-
thing was wrong. The spider was left unprotected on the-
ground while she made a number of long excursions without it,
sometimes being gone as much as fifteen minutes. On coming
back from these trips she would return to the task of squeezing
the legs with such energy and persistence that we expected to-
see them drop off. Then she would run over the ground in
all directions, looking under lumps of earth and stones and pok-
ing her head into every little hole. A¥as she trying to find
some suitable spot near at hand t^ take the place of the one
which she had prepared or selected at a distance?

B

Diagram of road over which spider was carried by P. scelestus.

One hour from the time of her arrival at this place, and twa
hours from the time that we began to watch her,, she flew away
and was gone for an unusually long time. We can only sup-
pose that when she absented herself in this way she was visiting
the spot to which she wished to convey her booty. On her
return she seemed to be filled with a new idea, for after climb-
ing to the top of a tall stout weed that grew near by, she came
down, seized the spider, and tried to drag it up the stem. Per-
haps she meant to lift it to such an elevation that she could'
fly with it, but it was too heavy for her and fell after she had
raised it to a height of three inches. She then flew away again,
and on her return we caught her, fearing that she was becom-
ing discouraged and that she might presently depart to be seen
no more. Had there been any prospect of her solving the dif-
ficulty that beset her our patience might have held out to the

THE SPIDER RA VISITERS. 157

'end, but this was evidently a case in whicli there was a failure
of instinct, or intelligence, or whatever faculty was concerned.

More than a year passed before we had another opportunity
•of solving this problem of scelestiis, and the pleasure with
which we hailed her second appearance in our garden may be
easily imagined. This time the wasp had made her nest but was
not ready to fill it, and when we first saw her she was ninning
about, without any particular aim in view, although at the time
we supposed her to be hunting. Before long she went and took
a look at the nice round hole which she had made near the
fence that separates the garden from the woods. The earth that
had been taken out had either been carried to a distance or had
been swept away after the digging was completed, for there was
no pile to be seen. This was at two o'clock of a cloudy after-
noon. It may be that she needed the stimulus of sunshine to
make her hunt, or perhaps she realized that what was left of the
^ay would not give her sufiicient time to capture het spider and
bring it home. At any rate she spent the remainder of the
afternoon in making short excursions around her nest. We
could find no reason for these from the utilitarian standpoint,
unless she was making a careful locality study of the neighbor-
hood, and this seems improbable since they were all in the di-
rection of the garden, while her hunting expeditions, when the
time came for them, carried her in the opposite direction, into
the woods.

Whatever their object, the trips took her from ten to twenty
feet from the nest, each occupying from fifteen minutes to half
an hour. At every return to the nest she flattened herself out
on the ground and wriggled in the dust, and then dragged her-
self all around it in the strangest manner. Perhaps these ac-
tions were indications of pleasurable emotion. We had seen
"them once before, in Priononyx afrata just before she carried a
locust into her nest.

At a little after four o'clock she began to investigate, very
■carefully, the plants and grasses that immediately surrounded
her hole, showing an especial interest in one bunch of clover

158 THE SOLITARY WASPS.

that grew four inches away. Into this she finally vanished^
and peering curiously among the greenery, we discovered her
hanging to a leaf, which was sheltered by thick foliage on all
sides. Here she remained motionless and probably fast asleep
until sundo^vn, when we left her for the night.

When we went to the garden at eight o'clock on the follow-
ing morning, scelestiis was still sound asleep in her leafy bower.
We thought it best to awaken her, for a large Agalena na^via
had spread her web just below, and if the wasp should drop upon
it nothing could save her. We therefore aroused her gently,
whereupon she crept slowly up the stem and taking her stand
on the highest point, surveyed the world. Then, after stretch-
ing herself sleepily, she made her toilet, cleaning off her wdngs
and legs, and washing her face with her feet like a cat. When
these duties were finished she walked slowly about for an hour,
visiting her nest every now and then. Suddenly, at half past
nine o'clock, her whole manner changed, and seeming very
much excited she ran rapidly along, parallel with the fence,
for fifteen or twenty feet, and then, rising on her wings, flew
far away into the woods. She had evidently gone hunting at
last, and we watched eagerly for her return. She was not suc-
cessful at once, however, for at half past ten she came back
without anything, stayed at the nest for a few minutes, and
then flew to the woods again with the same excited manner as-
before. Perhaps she had already caught her spider at some
far distant spot, and was getting her bearings preparatory to
bringing it home, but it was half past one when she suddenly
appeared, five or six inches from the nest, coming backward
through the fence, and dragging a large Lycosid. This she
laid down close by, and began to bite at the legs quite after
the manner of the wasp we had seen the year before. Her
movements were full of nei'V'Ous excitement, in marked contrast
to those of the previous day. Presently she Avent to look at
her nest and seemed to be struck with a thought that had al-
ready occurred to us — that it was decidedly too small to hold
the spider. Back she went for another survey of her bulky

THE SPIDER RA VIS HERS. 15»

Yictim, measured it witli her eye, without touehing it, drew her
conclusions, and at once returned to the nest and began to make
it larger. We have several times seen wasps enlarge their holes
when a trial had demonstrated that the spider would not go in,
but this seemed a remarkably intelligent use of the comparative
faculty. Her method of work was peculiar. St-anding in the
tunnel with her head down and her abdomen curved under, she
bit the earth loose with her mandibles and pushed it under her
body and beyond the tip of the abdomen. When a little had
accumulated she backed out, holding it in this way.

While she was thus employed the spider was attacked by a
very tiny red ant, that could not by any possibility have stirred
it. When the wasp caught sight of this insignificant marauder
she fell into a fit of wild fury and bending her abdomen under,
seized the ant again and again in her mandibles, and flung it
backward against the tip of her sting. The little creature finally
escaped, seeming none thiC worse for the rough handling to which
it had been subjected, while the wasp, still trembling with ex-
citement, gTasped her spider and rushed off to a distance of
several feet, carrying it up on a weed and depositing it there.
The labor of excavation was then resumed and after a half
hour's work, Avas completed to her satisfaction. Coming up
head first she flattened herself out on the ground, and sprawling
thus, dragged herself all around it. The spider was now brought
to the nest, being left once on the way while she ran in and out
again, and was taken in after a new and original fashion. Back-
ing in herself she seized it by the tip of the abdomen and
dragged it down without any trouble, since the legs were gently
pushed up over the head and made no resistance.

In two minutes she emerged from the opening, and standing
on the four posterior legs, with her abdomen hanging down
into the hole, scratched the earth backward with the front legs
and mandibles. As it fell in she pushed it down with the ab-
domen, and as the hole filled she raised hei*self higher and
higher on her legs, still using the tip of the abdomen to work
the material into place.

160 THE SOLITARY WASPS.

When the operation was nearly completed we caught the
wasp and opened the nest. The egg, which was placed upon
one side of the abdomen of the spider, did not develop, because
its intended victim, not being held in place by the earth of the
nest, knocked it off on the second day. We transplanted it to
the abdomen of an E. striw which had been more thoroughly
paralyzed by quinquenotatus, but in vain.

Among the French wasps the yellow-winged Sphew first
makes her nest and then captures her prey, which is so small
that she can carry it easily. The Langiiedocien species on the other
hand takes a very hea^^y victim and digs her hole near the place
of capture, wherever that may be. How much better is this
adjustment than the one that we see among our PompiUdae,
where quinquenotatus first catches her strioo which is so small
that she can easily fly with it, and leaves it exposed to many
dangers during the time that she is excavating its resting place,
while scelestus digs her nest and then goes far away to capture
the great spider, which she must drag painfully along for hours
before she can bring it home.

The victim of P. scelestus.

When we picked up the spider that had been stung by our
first example of P. scelestus, at a little after one o'clock in the
afternoon, it was limp and appeared to be dead. A careful ex-
amination resulted in the same verdict. "No stimulation brought
a response. At five o'clock, however, we succeeded in getting
a slight quiver of the tarsi, when stimulating the legs at the ar-
ticulation of the femur and trochanter. At nine o'clock on the
following morning, August eighteenth, the spider, which was
a full grown female, had almost recovered; she was so active
that when she was touched with the forceps she ran several
steps, and when the instrument was brought in front of her
she seized it with her falces and held it so firmly that she could
be lifted up and dragged about. She could co-ordinate her
movements, since she brushed off anything that touched her by
means of her tarsi. She was unable to see, since when threat-

THE SPIDER BA VISHERS. 161

ened in front she paid no attention until slie was touclied, wlien
she threw up her first legs in the way that is characteristic of
spiders, and snapped with her falces. When picked up she bit
the hand severely. She was evidently a good deal affected by
the poison and did not act like a normal spider. Voluntary
movement was not aboKshed but she had little initiative and
remained quiet unless disturbed. A little later in the day she
ran a few steps without being touched.

On the nineteenth there was but little change. When the
tip of one of the legs was touched it was drawn up toward the
body, and by touching the first, second, and third in succession
they would all leave the ground, but when the fourth was stim-
ulated and drawn up one of the others came down so that she
always had one to support her. On August twentieth, when
placed on her back she was unable to turn over, although she
made a great effort to do so. On the twenty-second she ate a
fly, and on the twenty-third she caught an uninjured fly which
was put into her glass. From that time on she caught anything
that was put into her glass and seized with her falces any ob-
ject that was used to touch her. One day we gave her a large
stink-bug, one of the Pentatomldae. She at once caught it but
when it sent off its terrible odor she dropped it and drew back
in haste. The odor was so powerful that the spider fell over
on to one side thro"\nng up all the legs on the side toward the
bug, in the most comical fashion. We now feel quitei confident
that stink-bugs are protected from spiders.

Up to the thirteenth of l!^ovember our captive changed but
little. She caught flies when they came in contact with her,
turning so quickly that they were seized before they could
escape, but when they walked in front of her she evidently did
not see them, being quite blind. She ran rapidly and had com-
mand of all her parts, and yet voluntary movement was not
quite normal. Perhaps her condition might be expressed by
saying that she was more sluggish than is usual in her species,
moving about in her glass much less than other specimens of
her kind have done when we have kept them in confinement.
11

162 THE SOLITARY WASPS.

Tlie result of the sting of tlie wasp, then, was in the first in-
stance completely to paralyze and to render the spider inca-
pable of any movement whatever. This condition lasted from
about eleven in the morning to five in the afternoon, or six
hours. In the second stage she slowly recovered, the effect
of the poison passing off gradually, so that by the next morn-
ing she was able to move about and to defend herself with
considerable vigor. Within a few days she was in fair condi-
tion, being able to walk or run, to bite and to catch flies, but
she remained permanently blind. Taking these facts into con-
sideration it is plain that the ganglionic mass in the cephalo-
thorax was seriously affected by the poison of the wasp. The
whole mass was involved since all the parts were perfectly
paralyzed. The paralysis could not have been the result of in-
jury to the ganglionic structure since recovery took place within
twenty hours, therefore the disorder was functional not struct-
ural, excepting as regards that part of the nervous mass that
was actually pierced by the sting, and in which the tissue was
destroyed. To judge from results, the part which was thus
affected was that which supplies the nerves of sight. In regard
to the general paralysis from diffusion of the poison, we should
expect it to be of brief, or of permanent duration, according
to the amount injected, and our experiments upon spiders and
crayfish have given these results. A crayfish many times as
large as this Lycosid was completely paralyzed when stung by
a wasp at a point remote from any ganglion, but in a few min-
utes the effect of the poison passed off and movement was re-
stored. A repetition of the sting either killed the animal or
reinstated the paralysis. The table given in the chapter on
Pelopaeits should be consulted in this connection.

The spider under discussion having made an almost com-
plete recovery, except as to vision, we determined to try the
effect of a severe woimd of the nervous mass in producing pa-
ralysis. At three o'clock in the afternoon of November
twenty-ninth a fine needle was pushed through the center of
the thoracic ganglion of a spider from the ventral side. Pa-

THE SPIDER BA VIS HERS. 163

ralysis at once ensued althougli tlie legs twitched and respond-
ed irregularly to stimulation. Fifteen minutes later the first,
third, and fourth legs on the right ^ide kept quivering as the
spider lay on her back. At the end of an hour she turned over,
after some struggling, and took two or three staggering steps.
When picked up for examination she bit the finger so that the
fang penetrated the skin, and as the hand was raised she held
on so that she was lifted from her feet. She regained her
strength gradually and by ten o'clock of the same evening she
moved about, but as the legs on the two sides did not act to-
gether she went sideways instead of straight ahead. There was
but little change from this condition until the second Decem-
ber when the second leg was drawn up to the body and never
moved again. On the fourth she was less active, growing
weaker and weaker through the day, and on the afternoon of
the fifth she died. She had lived for six days with only par-
tial paralysis after being wounded in ihe ganglion by an instru-
ment six or seven times as thick as the sting of a wasp. Dur-
ing this time she had been able to turn over, to run when
touched and to bite violently. One drop of wasp-poison seems
to have more potency in producing paralysis than any ordinary
wound of the nervous system.

Our second example of the victim of scelestus was, when
taken from the nest, perfectly limp and motionless, giving no
response to stimulation. Within twenty-four hours the effect
of the poison had largely passed off, and by the third day the
spider had recovered her normal health and was released.

This spider and the one taken by our other scelestus, be-
longed to the same species.

When we take the rapid recovery of the spiders into consider-
ation we see that the comparatively small size of the nest is
an important factor in the drama. The prey is buried alive in
the fullest sense of the term but is wedged in so tightly that
not the slightest movement is possible, and thus the egg is pro-
tected.

164 THE SOLITARY WASPS.

Agenia homhycina Cresson.

In the literature of tlie hymenoptera references have been
made from time to time, to certain wasps that cut off tlie legs
of spiders or other creatures before storing them away, but
observations on the subject have been rare and not very def-
inite. Kirby and Spence* quote from M. Cassigny to the
effect that he has seen species of Sphecina, in the Isle of
France, drag into their holes dead cockroaches, and that when
one happened to be too large to enter, the elytra, and come of
the legs were removed so that it could be drawn in without
difficulty. Brehm, in the "Thierleben," says that Agenia
punctata builds nests of mud and places in each cell one mod-
erately large spider from which she has first removed all the
legs. The most interesting notes on the subject have been
made by M. Goureau* who gives an account of finding two
spiders that had been mutilated by wasps, one of them having
had all of the legs cut off and the other, all but the first pair.
At another time a wasp that was flying near him let fall a
spider which he captured before it could be recovered by the
owner. The wasp escaped so that he could not determine the
species, but the spider's legs had been removed. He conclud'
ed that instead of stinging the spiders the wasps had mutilated
them so that they could not run away. He does not seem to
realize that death would certainly result from such an operation.

Yespa germanica often cuts off the wings of a dead w^asp or
even cuts its body into two parts, before flying away with it,
but this is only when the captured insect is too large to be
handled in any other way; and Pompilits fuscipemiis some-
times cuts off one or more legs from her spider, although with-
out any regular method of procedure.

"We once saw a wasp of the species Agenia homhycina carry-
ing a spider (an adult female Maevia vittata) from which all
the legs had been cut off excepting those of the first pair. She

*Iiitroduction to Entomology, 7th edition, p. 562.

*Ann. Soc. Ent. de France, 1839. Tome VIII., pp. 539-542.

THE SPIDEB a A VISHERS. 168

held it by one of the remaining legs and went forward, some-
times half flying. We took the spider from her and found
that it was dead.

We have recently received from Mr. George Dimmock a
very interesting account, together with the specimens, of a find
of a set of cells of hombycina. We give the description from
the notes that he has generously placed at our disposal:

September, 16, 1895. Found a wasp nest under a stone at Canobie
Lake, N. H. It consisted of sixteen small mud cells about 15x8 mm.
(PI. IX., fig. 3). Eight of these cells contained spiders — each cell a
single spider — and all the spiders were of one species, Lycosa Kochii,
Two were immature females, three mature females and three, mature
males. In the other cells were the remains of single spiders more or
less eaten. With one exception these spiders were deprived of all
their legs but not of their palpi. One spider retained, in addition to
the palpi, its anterior pair of legs (PI. IX., fig. 2). One cell contained
a spun-in-pupa, and in the remaining cells (i. e., eight) the spiders
were so far devoured that the species could not be readily deter-
mined. In one cell was an egg fastened upon a spider and in others
larvae in various stages of development. Thus all stages of the young,
from egg to pupa (and imago) were represented, only a single imago
being found. She did not attempt to defend the nest but hid in the
grass near at hand."

Thus the statements of Goureau and Brehm are confirmed
and there can be no, doubt that some of the solitary wasps have
the remarkable habit of cutting off some or all of the legs of
the spiders that they use for storing their nests. When Mr.
Dimmock sent us the spiders and cells, we found, upon exam-
ination, that a single spider was just large enough to fit com-
fortably one of the cells. If the legs had not been removed
the victim would have beenj too large for its coffin. The habits
of this wasp prove that in this instance at least, a dead and con-
siderably mutilated spider serves the larva for food quite as well
as a paralyzed caterpillar does in the case of Ammophila.

Agenia architecta Say.

For a few days before the fourth of July our flag stood in
the corner of the porch, and when we unfurled it, on the na-

166 THE SOLITARY WASPS.

tional holiday, we found fastened to it, and hidden in its folds,
three dainty little mud nests, eight millimeters long by five
wide. Each nest contained a wasp larva and a dead spider.
The nests were probably made one day apart since the larvae
spun their cocoons on the seventh, eighth, and ninth of July,
giving a shorter larval stage than we have ever known except-
ing in the case of the little grasshopper wasp, Tackytes sp. ? On
July twenty-ninth a male of A. arcMtecta issued from one of
the nests, and before August second two females had appeared
from the others.

On the seventeenw.h of July we found two nests of arcMtecta
fastened to the inside wall of the boat house. The larvae had
already pupated and by the twenty-eighth of the month the
wasps had flown away. Erom its rapid development it seems
probable that this species has two generations in one season.

THE ENEMIES OF THE ORTHOPTERA. 167

CHAPTER XIII.

THE ENEMIES OF THE ORTHOPTERA.

Tachytes spA
Plate XI., fig. 5.

Early in September this little black wasp suddenly became
very common in the garden. The first one that we saw was
going forwards in a series of long jumps, carrying a small grass-
hopper which was held by the base of the antennae. She soon,
doubled on her tracks and it became evident that she did not
know her way, but after going around in circles for two minutes
she ran into her nest. When she came out she spent a long
time in circling around, flying close to the ground in wavy,
snaky lines, occasionally alighting to run a few steps, but in
spite of this locality study, ten minutes later, when she came
jumping along with her second grasshopper she had lost her
nest again and hunted about just asi before, twice going directly
over it without seeing it. While she was thuS occupied another
wasp of the same species attacked her and tried to get possession
of the gra^hopper, but the rightful owner was able to defend
it. At last it was stored away and she proceeded to fill the
nest, scratching the earth in with her first legs and working it
down with the tip of the abdomen. She worked quietly but
steadily for ten minutes, closing the place neatly, and then
brought bits of leaf and pieces of earth to cover it all over.

On the same afternoon we saw another of theses wasps dig-
ging her nest, but she was so much disturbed when we came
anywhere near her that we were obliged to retire. On the next
day we saw her astride of a small grasshopper jumping along
like the one of the day before. She too had great trouble in
finding her way. When she reached the nest she laid her prey

168 THE SOLITARY WASPS.

down while she went inside for a moment, and then, coming
ont, seized it by the antennse and backed in with it, instead of
taking it in forwards as was done in the other case.

Another wasp of this species canied a much larger grass-
hopper which was so heavy that she could not jump with it, but
was obliged to keep to the ground. In this case only one was
used instead of two, which is the usual number. This wasp was
first seen at a distance of twenty feet from her nest, and yet
she went straight to the right spot without the least confusion,
showing that some individuals of the species have a better idea
of locality than others.

The nest of this species is a short, shallow tunnel with an
enlargement at the end, within which are placed the grasshop-
pers, on their backs, with their heads in. (PI, XI., fig. 5.)
Earth is packed solidly into the tunnel but not into the cavity
at the end.

We took two eggs of this species. Each was placed across
the thorax of the grasshopper at the base of the neck, on the
ventral side. Both hatched at the end of thirty-six hours from
the time they were laid, ate for three days, and then spun their
cocoons. One of them ate only one small grasshopper, leav-
ing a second one untouched, while the other finished the large
grasshopper that formed her sole provision.

The grasshoppers taken from the nests, five in number, were
in all cases alive, there being a quivering of the mouth parts,
and in some cases of the legs also, v»dthout any stimulation.
This condition lasted for twenty-four hours from the time the
poison was injected. After that they became quiet but re-
mained alive until they were destroyed by the larvse.

It is a curious thing that in these wasps is found the perfec-
tion of that method of paralyzing the prey which is so much
dwelt upon by Fabre, although from their habits this fine work-
manship is not of the slightest use to them. They entomb
their victims underground, Avhere the conditions are favorable
to their preservation, and the extremely short period that

THE ENEMIES OF THE OBTHOPTEBA. 169

elapses between the laying of the egg and the spinning of the
cocoon makes it a matter of indifference whether the grass-
hopper is alive or dead, since in any case it would be eaten be-
fore decomposition set in.

Lyroda suhita Say.

In our summer work we often found ourselves wishing that
we could be in half a dozen places at once and could chase sev-
eral wasps at the same time, and never did we feel these desires
more keenly than on the twenty-ninth of July, when, after
spending the best part of an hour in watching the hunting of
an AmmopJiila we were obliged to choose between following
her to a possible conclusion, and giving our attention to a little
black wasp which we now saw for the first time. This wasp
was running around a bunch of clover in a nervous, agitated
manner, as though she were oppressed by some great anxiety.
The chance of discovering something entirely new decided us
to relinquish our Ammophiline hopes and w^e sat down at the
feet of our new teacher.

We could not see anything remarkable about that bunch of
clover but certainly the spot had some strong attraction for the
uneasy little wasp. She ran off first in one direction and then
in another. She circled about and made short flights now this
way and now that, but always returned. At last she betrayed
the secret of her interest by descending to the ground and pick-
ing up a small black cricket which had been lying close by all
the time. She flew up into the air with it but even now did
not leave the neighborhood, continuing to fly about from place
to place, alighting now and again on the bean plants.

After this performance had lasted for five minutes she
brought her burden back to the same spot that it had occupied
before, laid it down, and without vouchsafing to us any expla-
nation of her conduct, began to burrow into the soft earth.
She went down head first, backing out with the dirt, which she
carried with the front legs. While she was thus occupied we

170 THE SOLITARY WASPS.

defended her booty against two liunting parties of ants wliicli,
at different times, fell upon it and would certainly liave carried
it off if we had not been at hand.

It took the wasp twenty minutes to open the burrow, al-
though, as we afterward learned, it had been excavated before.
At the end of that time she turned around inside, came out head
first, and dragged the cricket within.

"We at once opened the nest but found it impossible to fol-
low the tunnel on, account of the crumbling of the earth. In-
deed we almost concluded that we were doomed to complete
failure for it was not until we had gone down between six and
seven inches that we found, in a little pocket, our wasp in com-
pany with three crickets upon one of which was a larva a day
or two old. At the time we knew nothing of the habits of
Bemheoe spinolae and we were much astonished to find a wasp
which evidently fed her young from day to day.

The contents of the nest were carefully conveyed to our
wasp-nursery at the cottage. The cricket that we had seen
taken in was dead as was also the one upon which the larva
was feeding. The third one was alive as was shown by a
rhythmic movement of the palpi on the right side. By the
next day, however, this one also was dead.

On the morning of the third day, July thirty-first, the larva
had eaten all of the first cricket and the greater part of one of
the others, leaving only the large hind legs. Supplying the
place of the mother we killed two more and put them into the
tube. One of these was eight millimeters long, this being
about the size of those which the wasp herself had caught, while
the other was of another species and much larger, being thirty
millimeters long. Its size and kind however made no difference
to the larva, which attacked this one next although there were
two small ones yet untouched. It ate only half of this big one,
however, and then passed on. On Aug-ust second we gave it
two more small crickets and for that day and the one following
its good appetite continued, but on Aug-ust fourth it stopped
eating. We thought that its larval hfe must be completed, and

THE ENEMIES OF THE ORTHOPTERA. 171

expected to see it spin its cocoon, but sometlung was lacking
which, we were too ignorant to supply and on August fifth it
died. It had eaten six small crickets and half of the large one,
which was equal to about two more. Thus ended our only ac-
quaintance with this interesting little wasp.

Priononyw atrata St. Farg.

PL XIV., fig. 4.

It had rained heavily in the night, and when we went down
to the garden at a little before noon of August foui-teenth, al-
though the sun was sliining brightly, we found that everything
was still too damp to suit our fastidious friends, the wasps. One
of them, however,! had begun a task on the day before and felt
that she must go on vdth it whether the weather suited her or
not, for in walking through the strawberry bed we disturbed a
big black Prionmiyjp that flew up from her nearly completed
nest at our approach. At one side of the opening was a pile of
freshly excavated earth, and beneath this was the material that
had plainly been taken out the day before, since the pellets
were wet and beaten together by the rain. Our wasp did not
go far but settled down on the ground near by and remained
quiet for some minutes. Then she flew, over the adjoining row
of plants into the next space and, after running about a little,
found her prey — a big brovm locust (D. Carolina) which had
been deposited there while she went to give final touches to the
nest. She was satisfied now with merely taking a look at it,
after which she rose on her v^dngs and circled widely about,
alighting here and there, but not going back to the nest. When
on the ground she flattened herself out, in an odd way, lying so
that the ventral surface of the body was in contact with the
earth. We had never before seen just this action in a wasp,
but afterward we observed the same thing in P. scelestus when
she was in the neighborhood of her nest. After ten minutes
had passed in this way she went back to her burrow and took
out half a dozen loads of earth, running down and then back-

172 THE SOLITARY WASPS.

ing out witli it in ber mandibles, and not using ber legs at alL
Tben sbe went back to, ber locust, wbicb, in tbe meantime, bad.
been jerking its legs up and down and sbowing plainly tbat it
was not in a state of suspended animation. Sbe caugbt it by
one antenna, straddled it witb ber long legs, and ran along
briskly, very mucb like an Ammophila until sbe bad reacbed
tbe open space between tbe rows of plants in wbicb ber nest was-
situated, but bere, at a distance of about tbree feet from tbe
nest itself, sbe dropped it, and walked deliberately away, past
tbe nest and considerably beyond it. Now again sbe flattened
berself out close to tbe ground, and remained in tbat attitude
for five minutes. Wbetber because sbe was not quite reader
to lay tbe egg, or for some otber reason, it was evident tbat sbe*
was in no buny. At last, bowever, sbe approacbed tbe locust
again. Just before sbe reacbed it, it gave a jump as if in nor-
mal bealtb, but did not attempt to fly. We certainly ex-
pected tbat sbe would sting it again, but no, sbe straddled it
as before, bolding it at tbe base of tbe antennas, and carried it
to tbe nest. Here it was dropped wbile sbe ran in for a mo-
ment, came out, and tben backed in again, caugbt it, still by
tbe base of tbe antennae, and dragged it out of sigbt. Wben,,
after a few minutes, sbe came out, we caugbt ber and put ber
under a glass witb anotber locust, but sbe would not toucb it.

Tbe nest was not excavated until two days later, exactly
forty-eigbt bours from tbe time tbe egg was laid. It ran in
obliquely for two incbes, and bad no pocket. Tbe locust bad
been pulled in bead first witb its long tbird legs stretcbed out
bebind, and tbe eartb bad been pressed in around it so closely
tbat it could not move. As soon as we began to remove tbe
eartb we were conscious of a violent kicking down in tbe dirt.
Tbe position of tbe bead was indicated by a long antenna wbicb
stuck up tbrougb tbe covering. As tbe eartb was gently pusbed
away the egg was revealed. It Avas fastened to tbe upper side
of tbe body (tbe locust lay on its rigbt side) in tbe skin just
above the tbird leg, so tbat tbe long curved free end extended
over the thigh. As soon as the locust was uncovered it jumped

THE ENEMIES OF THE OBTHOPTEBA. 173

away and would have departed entirely if we liad not caught
it. We held its legs so that it could not kick, but it twitched
the muscles of its skin so violently that the egg jumped up and
down. It probably could not move at all in its narrow prison
but now that it was taken out the only chance of saving the
egg was to kill the locust, and therefore its gTotesque head was
removed, not without sympathy for its hard fate. Before the
operation the mouth parts, antennae, and first and third pairs
of legs seemed in perfect condition. The second pair did not
move unless touched and then only feebly. The wings were
motionless.

In spite of our precautions the Qgg never hatched. Probably
it had been too violently shaken up already.

This species is evidently one of those that first prepare the
nest and then catch the wherewithal to fill it. She stings it
in such a way that it cannot fly, and the poison temporarily
affects its legs also, but there is at no time a condition of im-
movability excepting from mechanical causes, the wasp relying
upon tight packing to secure the necessary degree of quiet.

We afterward saw this wasp occasionally in the garden, ap-
parently looking for a place to dig her nest, but flight always
carried her beyond our power of following before she found a
spot that suited her.

Chlorion coeruleum Linn.

PI. II., fig. 3; PL XI., fig. 4.

As we climbed the steep slope that leads to the level ground
on the top of the island, one morning late in August, we saw
a magnificent great steel-blue wasp coming from the grass that
fringed the edge of the cliff, carrying in her mandibles a good
sized cricket. After running a little way she rose and flew
lightly for about eighteen feet, and then, after pausing long
enough for us to overtake her, ran forward again to a large
hole on the bare liillside. To one side of the opening was a
pile of earth made up of large pellets. Into this hole went our
wasp, without any hesitation.

174 THE SOLITARY WASPS.

When she came out, at the end of five minutes, we secured
her and at once opened the burrow. The tunnel was large and
ran down to a pocket (PL XI., fig. 4), in which were seven
crickets (Gri/llns ahhreviatns Linn.), neatly arranged on their
backs with their heads inward and their long hind legs pro-
jecting somewhat into the tunnel. They varied in length from
fourteen to seventeen millimeters. All of them were alive and
moved vdthout any stimulation. On the fifth one taken out was
the long, cylindrical e'gg, which was placed on the right side
of the body at right angles to its length, the fre^e end being di-
rected upward. It was now only nine o'clock in the morning,
so that it seemed likely that the egg had been laid the day be-
fore, on August twenty-seventh. It hatched on the morning
of the thirty-first. The larval stage oc^jupied ten days, during
which time five crickets were eaten, the cocoon being spun on
September ninth.

The cricket to which the Qgg was fastened kicked violently
through the first, two days after the hatching, striking the larva
continually. The other crickets died from day to day but were
accepted Avithout question by the larva.

Harpactopiis ahdominulis Say.

PL II., fig. 1.

"Warm air, brilliant sunshine, and the wide expanse of the
onion-bed made the conditions for wasp-hunting quite perfect
on that fifth day of July when we first saw Harpactopiis ah-
dominalis. The large, handsome wasp, dressed, after the fash-
ion of so many of her relatives, in black with a i*ed girdle, was
hunting about among the plants with an anxious, hurried air,
which seemed to indicate that she was looking for a nesting-
place, but when she came to the spot that she wanted, a few
rapid scratches opened a burrow that had already been made,
showing that this species, like Ammophila, first digs her nest
and then hunts for her quarry. If she had first secured her prey
and then made the nest it would have been open.

THE ENEMIES OF THE OBTHOPTERA. 175

As soon as she had opened up the way she began to hunt
about as before, running hither and thither with great rapidity
and showing by the excitement of her manner that some im-
portant erisis ia her affairs was at hand. After three or four
minutes she stumbled upon a large dirt-colored locust (Disos-
teria Carolina), which was lying on the ground about two feet
away. She seized her bulky prize by the base of the antennae
and carried it, right side up, to the edge of the hole, where it
was dropped while she backed in. Then, grasping it in her
mandibles, she dragged it out of sight. When she reappeared
we tried to catch her, and she flew away. A few minutes later
she returned and began to fill the hole but again we disturbed
her, and this time she was, perhaps, impressed with the idea of
danger, for she stayed away from the place for at least half an
hour. At the end of this time we gave her up and turned our
attention to something else, but when we came back later in the
day we found that the hole had been filled and the spot neatly
smoothed over. "We dug out the locust and found the long
cylindrical egg fastened on the right side, just above and over-
lapping the articulation of the third leg with the body. The
locust was quiet but the abdomen pulsated and under stimula-
tion the antennae quivered. By the next day it had partly re-
covered, and from the seventh to the tenth of July it was quite
lively, kicking vigorously when touched. On the eleventh
it began to lose strength and on the fourteenth it died. The
egg never hatched.

176 THE SOLITARY WASPS.

CHAPTEE XIV.

THE MUD-DAUBERS.

Pelopaeus.
PL II., fig. 5; PL X., figs. 1-3.

This genus is widely distributed, being found in all regions
of the earth, and contains a large number of species. Of these,
two are common in this locality, Pelopaeus cementarius, or
Yellow Mud-dauber, and Pelopaeus coeruleus, or Blue Mud-
dauber. The latter is much the more common of the two, and
its irridescent steel-blue color makes it one of the most beauti-
ful of our wasps. Por a number of years we have given a great
deal of time to the habits of this genus and we are far from
agreeing with that mcst distinguished observer, Pabre, in the
opinion that its role is one of mediocre interest. The large
measure of individuality that we have found in the habits of
the different individuals that w^e have studied, may, it is true,
be only the natural result of the large number of our observa-
tions. Perhaps all of the solitary wasps would be found to vary
as widely as the mud-daubers if several hundred examples of
each species were carefully studied. Be that as it may, it is
certainly true that our mud-daubers possess all the charm of
marked individuality, with few defects of temper, and that they
lead most industrious and interesting lives.

We have not been able to determine how many generations
there are in a year, but there are certainly two, and perhaps
three. In May or June the female makes her appearance and
begins the work of establishing a home. Almost invariably
she decides to build for herself, although now and then she uses
an old nest. This habit of occasionally renting an old house
is common to a large number of wasps that under ordinary cir-

THE MUD-DA UBERS. 177

cumstances prefer to r-onstnict their cwn domiciles. "We have,
in several instances, seen two or three queens of our Polistes
fusca join together and utilize a nest of the preceding year,
each one clearing up three or four cells wherein to start her
colony, while close by other queens were starting new nests,
each building one for herself, being unable to find anything
that suited her among the numerous old ones that hung about
the place. This intelligent use of old habitations on the part
of Pelopaeus is not very frequent, the instinct to build seeming
well-nigh imperative.

The spot chosen for the nest may be in a bam, up among the
rafters, in an out-house, under the roof of a porch, or indeed
in any sheltered place where it will be protected. Originally
they built under over-hanging rocks and in hollow trees, as they
still do if better places are not to be found, but when near hu-
man habitations they make use of the more convenient positions
which they offer. Fabre says that the Pelopaei in France
build on chimneys inside of houses, and he even believes that
they examine a chimney to see whether it is in use, so that they
may be assured of sufficient warmth for their young during the
winter. Our wasps are less provident, perhaps because they are
entirely able to withstand a low temperature, and so have not
had their intelligence so highly cultivated as is the case with their
French cousins.

Having selected a place the wasp goes off for her building
material. She will use almost any kind of earth if only it be
damp. We once found a nest consisting of a group of fifteen
cells, four of which, in the center, were constructed entirely of
pure white plaster, making a striking color contrast with the
mud colored cells which surrounded them. In gathering her load
of mud, the wasp forces her head down into the soil, raising her
body into a nearly vertical position. While she works she gives
vent to her feelings in a loud contented hum. She ceases to
sing as she rises, with a lump of mud held in her mandibles.
On arriving at the scene of her building operations she places
the soft mud in position, using her mouth, mandibles, and feet,
12

178 THE SOLITARY WASPS.

patting it both inside and outside as the wall grows. The lay-
ers are put on in a more or less oblique position, and each load
makes about half a ring in the larger parts, or a whole ring
near the bottom of the cell. From thirty-two to forty loads
complete the cell^ which is composed of from sixteen to twenty
layers. As a usual thing one cell is placed against another
until a large mass is formed. The wasp adds nothing to the
mud, depending upon its drying for the necessary firmness, and
if, by some accident, the rain strikes it the whole becomes soft
and falls to pieces. Since one wasp builds in several different
places in a summer it is difficult to say what should be con-
sidered a fair amount of work for a season. Most commonly
there are five or six cells in a group. The largest number
that we have ever found was twenty-one. Probably we should
have found the average number higher if we had not collected
while the work was still going on, instead of waiting until the
season was over.

The cells, when first finished, are elegant affairs, and with
the blue or yellow wasp standing on the rim, they present a
very pretty picture ; but soon all this is changed, for when a few
cells are done she brings pellets of mud and plasters them all
over the outside, hiding the contour of the rings and making it,
in very truth, the nest of a dauber. What it loses in beauty,
however, it gains in durability and strength, and as the later
cocoons must remain within through the winter we mil hope
that the thickness, of the walls serves as a protection when the
mercury goes down below the zero point. One wasp had too
much artistic sense to spoil the appearance of her work, but she
compromised with her instinct by bringing the extra amount of
mud and attaching it in lumps here and there over the whole
of the group (PL X., fig. 1.) We, ourselves, preferred this
style of architecture to the other. The chief interest of Pelo-
paeus lies in instances like this, of marked variation in an im-
portant instinct.

Almost all the cells that we have collected during the past

THE MUD-DAUBERS. 179

six years, or, to be more exact, five hundred and forty-six nests
out of five hundred and seventy-three, had their openings at the
top, the longitudinal axis being nearly vertical, while twenty-
seven were placed horizontally, with the opening at the side,
(PL X., figs. 2-3.) Eabre found chat in France, Pelopaeiis
always gave the cell a horizontal or slightly oblique direction
with the opening out or a little up. With our wasps the vari-
ation in the position of the cells was an individual affair, sinc3
one would sometimes change the direction of the cells she was
making. One fickle-minded worker built two with their open-
ings directly up, and then placed a third cell at right angles to
these with the opening out. Another made sixteen vertical
cells and then, changing her plan, placed two horizontally.
"We found another group of six, of which four opened up and
two out, and still another with five up and four out. So far as
we could see the one direction possessed no advantage over the
other. Maindron, in describing the habits of Pelopaetis in the
Indian Archipelago, says that what strikes him most in the
aispect of their nests is their great variability. He has nevsr
found two alike in exterior form, in volume, or in the number
of cells, and these also vary greatly, although they are almost
always oblong.*

So soon as the cell is done, even if it be late in the afternoon,
the wasp begins to lay in the food supply for her offspring. In
this she differs from most of her relatives, as few of them wiU
work after four o'clock. In favorable weather the blue wasp
often builds and stores a nest in a single day. The prey that
she seeks is spiders, and this- seems to be true of Pelopaeus all
over the world. They take spiders of many different kinds but
always spiders. If a wasp begins to put a coramon species into
lier nest she is very likely to continue with it until the cell is
full, but she exercises a wise eclecticism in her choice and saves
herself all the trouble that she can. In spring and through
mid-summer our wasps most frequently take Epeira strix, vul-

*Ann. Soc. Entom. de France, Tome VIII., p. 338.

180 THE SOLITARY WASPS.

garis, and juniperi, wliicli are very common at that time, but
their depredations are not confined to these species, as represen-
tatives of several families are often found in the same cell.
Hentz, the well-known arachnologist, said that he made some of
his rarest finds in mud-daubers' nests. Sex plays no important
part in determining the choice since when the males are abund-
ant they are commonly seized. In September, when many of
them mature, the proportion of the males to the females in-
creases. Dr. McCook, in his work on American spiders, says:*
"It is, however, true that in the gatherings of any individual
wasp there is apt to be a preponderance of a single species of
spider. Thus it would seem that a wasp starting out with
Epeira striw, for example, is apt to devote herself chiefly to
collecting that particular species." But after all the prefer-
ence, if any exists, is but little developed and propinquity is the
important factor in determining what arachnid is taken.

An extract from our notes will give an idea of the contents
of these cells.

Nest taken July 17 contained 9 Theridion tepadariorum.

Nest taken July 17 contained 16 E. strix, 1 Tliomisid.

Nest taken July 17 contained 10 young A. riparia, 4 Steadota
marmorata, 1 E. insularis, 1 unknown.

Nest taken July 21 contained 5 E. insularis, 3 Phidippus rufus (1
male and 2 females, all mature), 1 A. riparia.

Nest taken July 22 contained 9 Thoniisus ferox.

Nest taken July 22 contained 9 A. riparia, 5 Steadota marmorata.

Nest taken July 22 contained 15 E. lahyrintliea, 1 DendrypJiantes
militaris males, adult.

Nest taken July 23 contained 12 Xysticus sp.?

Nest taken July 23 contained 7 Phidippus 3-punctatus, 1 Xysticus
sp.?

Nest taken August 18 contained 9 Orbweavers, {E. insularis and
juniperi).

Nest taken August 18 contained 15 A. riparia.

Nest taken September 14 contained 1 Misumena oblonga, 2 E.
vulgaris (1 male), 2 E. juniperi (1 male), 4 M. asperata, 4 E. strix, 1 E.
Z-punctatus.

*American Spiders and their Spinning Work, Vol. :II, p. 386.

THE MUD-DA UBERS. 181

"We mig-lit add to these notes but it is not necessary as they
are fair samples of the hundreds of cells that we have exam-
ined. The number stored is as variable as the species. Wa
have found as few as four in a closed nest, and Hentz once
counted forty. They pack in as many as the nest will hold,
using the head to push them as close together as possible, the
legs of the spiders being bent in all directions without regard
to either their comfort or their life. They order their food by
the pound rather than by the dozen, as it is said very thrifty
people do with their eggs.

The method of capture is the most interesting as well as the
most important part of the life history of the solitary wasps.
One can scarcely overestimate the value of the observations of
M. Fabre in this field and the longer we study his experiments
the greater becomes our admiration of him and of his work. In
one of his chapters, while estimating the value of his own
achievements in different lines, he says that while the zoologist
will prefer one part of his work and the embryologist another,
that the philosopher who is concerned with the nature of in-
stinct will give the palm to his study of the predatory wasps.
He then goes on to say: "I am with these last. Without hesi-
tation I would abandon all the rest of my entomological bag-
gage for this work, which, moreover, was the earliest in date
and which has for me the dearest associations."

During the last three years we have tried many ways of dis-
covering the manner in which the Pelopaei sting their prey.
One plan after another has been thought out, tried and aban-
doned as useless. The quality of patience is worth cultivating
and we have found that unless one is possessed of a large stock of
that virtue together with a firm belief in Dar^vin's sentiment,
"it is dogged as does it," he had better abandon the study of
the habits of animals.

Having failed entirely in our experimental efforts to discover
the method of Pelopaeus we resolved to follow them in the
field. We jealously guarded the spiders that spun their webs
■on our cottage walls, in the hope that their enemies would

182 THE SOLITARY WASPS.

come there to seek them. ISTo devastating broom was allowed
to disturb them and they increased and multiplied wonderfully,
but the unreasonable wasps never came near them. We scarcely
knew what to do next, but just at this juncture a friend who
lived several miles away, sent us word that his cottage porch
was a favorite hunting-ground of the Pelopaei, and, thankful
for the opportunity, but wondering much why his cottage was
preferred to ours, we made haste to go over to the scene of
their operations.

The questions to which we wanted answers were these: How
was the spider seized? When and how many times was it stung?
Was the wound given with discrimination, a certain point in
the ganglion being pricked so that the spider might be paral-
yzed but not killed, or was it given after the manner of a nov-
ice in the art? Was there any malaxation?

To make sure of all these points during the brief instant of
turmoil that covered the capture of the spider was, perhaps,
asking too much. At any rate we had to content ourselves
with partial success. We had scarcely arrived at our friend's
cottage, when, to our great delight, a blue Pelopaeus came fly-
ing along, alighted on the wall, and began her search, creeping
into comers and cracks and investigating cottony lumps of web.
In a few moments a small Epeira strix (the only species to be
found on the cottage), was dislodged and at once dropped to the
floor of the porch. The wasp paid no further attention to it
but went on with her search. Three more spiders, one after
the other, were disturbed and dropped to the floor without being
followed. The fifth one discovered was a little larger than the
others and was seized by the jaws and first leg's of the wasp be-
fore it had time to escape. It was then rolled into a ball, or
at least so it appeared, and stung, then rolled a little more, and
stung again, and then carried off. We had scarcely drawn
. reath after this performance when a second wasp appeared.
This one dislodged two spidei-s, and then caught a third which
was seized and stung without any rolling and then instantly

THE MUD-DAUBEBS. 183

"borne away. A third wasp seized tlie first spider that slie found
and started on her flight at the same moment, stinging it on the
wing.

So the game went on while the three of us, for our friend
soon became infected with our enthusiasm, waxed warm with
the excitement and fascination of thei chase. As the hours went
bv some of the yellow mud-daubers appeared, adding to the in-
terest of the scene, although we could not see that their method
differed in the least from that of coeruleus.

Earely did they succeed in catching a spider until they had
dislodged two or three. Sometimes the spiders were followed
as they dropped, and were caught on the floor, but oftener the
wasp let them escape and continued her search on the wall. At
the moment of capture we could see that she bent her abdomen
under and inflicted a sting, but although we concentrated our
attention on the point we could not be sure as to just what part
was touched. Sometimes it was the under part of the abdomen
that seemed to be stung, but more commonly it was the cephalo-
thorax, underneath or at the side. Once, when the three of us
were watching the same wasp, we all agreed that the thrust was
given in the dorsum of the abdomen, but the whole thing was
done with such a rush that we cannot mate any positive state-
ment. It is, however, our impression that this first sting was
given anywhere, at random, with the object of producing a con-
dition of temporary quiet in the victim so that the next part of
the operation could be carried on with deliberation.

The second step in the procedure was commonly for the wasp
to alight upon some neighboring object, usually the branch of a
bush or tree, and sting the spider a second time. She now had
every opportunity for the operation of learned surgery, and
she was evidently in no haste, but the difl&culty of following her
as she flew, and her habit of alighting above our range of vision
made it almost impossible to see just what she did. She cer-
tainly remained on the branch for some moments, either resting
quietly or rolling the spider around and around.

184 THE SOLITARY WASPS.

As the fruit of that day's labor we saw twenty-six assassins
capture and poinard as many victims, and with, their actions as
a basis we may assert that the wasp very commonly stings her
prey twice, first at the moment of capture and again after she
has alighted near by, and that the method of operation gives her
every opportunity for the exercise of any skill that she may
possess.

Having failed then in our plan of studying Pelopaeus under
artificial conditions, and having met with only a moderate de-
gree of success in watching the wasps out of doors, we found
ourselves obliged to rely mainly upon a third method, that of
studying the condition of as many of the spiders as we could
gather, in the hope of deciding whether these wasps are so won-
derfully skilful as they are reported to be, or whether they are
novices in the art of paralyzing their prey. To the layman th€
results of a surgeon's work are much more important than the
method of his procedure, and the test of his skill is the per-
centage of recoveries among his patients. Since the wasp, then,
has been held up as an adept in the art of producing paralysis
without death, we thought it fair to adopt a similar test with
her, and so we set for ourselves the task of examining spiders
from the cells of Pelopaeus, to see how many were killed at
the moment of capture, or were so much injured that they died
shortly after, and how many had been stung with such discrim-
ination as to preserve them for many days alive, but motionless,
a store of fresh food for the larva of the wasp. It may be
urged that dead spiders serve this purpose as well as living ones,
but this is a separate question. The point to be first determined
is whether the instinct to sting a certain place is much or little
developed in these wasps.

"We examined in all fiv^ hundred and seventy-three cells. Of
these, forty had been freshly sealed up with the egg just laid,
or were still open, the process of storing not having been com^
pleted. Under these circumstances the spiders were from one
to three days old and gave valuable information as to the point

THE MUD-DAUBERS. 185

in question. A detailed account of all our observations would
be too tedious but we select a few typical cases under each bead.

Aug-ust 15. Took a nest containing fourteen specimens of Argiope
copJtitiaria from 1-4 to 1-3 grown. Egg on anterior part of abdomen.
The spiders were very closely packed together and although plump
and fresh were all dead.

July 23. Found nest with fourteen spiders, four alive, ten dead. Of
the dead ones four looked plump and fresh, and six were dry. They
were packed together even more tightly than usual, so much so that
the abdomens of the dry ones were crushed and glued together and
also to the walls of the nest. One spider was partly plastered into
the top of the cell where it had been closed. Those near the top
-were the freshest. A second nest gave us fourteen specimens of
Epeira junipcri, including many varieties of this variable species.
There was no egg, although the nest had been closed. This was the
finest looking and best conditioned lot of spiders that we have ever
seen. Thirteen of them were alive and one dead.

July 28. On re-examining the spiders of the second nest taken on
July 23, we found that nine of the thirteen were dead, three of these
being partly dry.

September 14. We took a nest of which the provisioning was not
quite completed. It contained fourteen spiders, eleven of them being
'dead and three alive. Twelve of them were very plump and fresh
looking, while two had their abdomens crushed and looked old. The
egg had not yet been laid. We repeatedly examined the spiders very
carefully with a magnifying glass and even tried them with alcohol,
which causes a good deal of movement in those that are only para-
lyzed, but they were certainly dead.

September 15, 8 P. M. Have spent two hours in working over the
spiders taken yesterday. The three are still alive, but there has been
no recovery among those that we pronounced dead.

September 26. The three are still alive. Four of the others are
very dry.

This will suffice to give a fair idea of the surgical skill of our
ravishers. It is plain that the most of the spiders are killed at
once, while a quarter or a third of them live for a period vary-
ing from one to twelve days, dying in the nest from day to day.
Among those taken from other nests were some that were so
slightly injured that they lived all the way from twelve to forty
•days.

186

THE SOLITARY WASPS.

"We liave tabulated below tbe results obtained from our study
of tbe forty nests above referred to:

Table No. 1. — Shoiving condition of spiders found stored in 40
nests — 1-4 days old.

Condition

OF Spidee.

Condition

of Spidee .

No. of
nest.

Total No.
in nest.

No. of
nest.

Total No. -
in nest.

No.
dead.

No.
alive.

No.
dead.

No.

alive.

1

1

1

2

21

8

2

10

2

.9
14
10

9
14
15

22
23
24

1
7
6

1
3
2

2

3

10

i

5

8

5

12

8
20

28

12

8

21

29

25

28
27
28

3
13

16

12
15

1

19

6

25

7

1
1

15

8

13

14

9

20

5

25

29

10

4

14

10

17

1

18

30

]

13

14

11

12

5

17

31

10

4

14

12

3

6

9

32

2

3

5.

13

15

2

17

33

7

1

8

14

5
1
9

8
2
4

13
3
13

34

35
36

15
5
11

15

15

5

16

2

13

17

5

6

11

37

1

5

6

18

13

6

19

38

1

13

14

19

8

10

18

39

6

4

10

20

4

1

5

40

11

3

14

316

177

493

Tbe table shows tbat about tbirty-tbree per cent, of tbe spi-
ders are so skillfully stung tbat tbey are only paralyzed, wbile
tbe remainder are so poorly stung tbat tbey are killed. After
deatb tbey begin to dry up but remain in good condition for at
least twelve or fourteen days. As compared witb otber species
of tbe same genus our wasps excel tbose of France, wbicb, Fabre
bas found, almost invariably kill tbeir prey at once, but tbey

THE MUD-DAUBERS. 187

fall far below some of those tliat are found in other parts of the
world. Monteiro, in his work, "Angola and the Kiver Congo"
(p. 323), says that he has opened many of the nests of Pelopaeiis
spirifex and has always found the spiders alive, though unable
to crawl away when taken out. "Whilst at Bembe," he says,
"I fortunately witnessed a fight between a large specimen of
these wasps and a powerful spider which had built its fine web
on my office wall. The spider nearly had the wasp enveloped
in its web several times, and by means of its long legs prevented
the wasp from reaching its body with its sting, but at last, after
a few minutes' hard fighting, the wasp managed to stab the
spider right in the abdomen, when it instantly curled up its
legs and dropped like dead to the ground. The wasp pounced
down on it, but I interfered, and picking up the spider placed it
under a tumbler to ascertain how long it would live. * * *
It lived for a week, and, although moving its legs when touched,
had no power of locomotion, showing that the poison of the
wasp has a strong paralyzing effect." Eversmann gives similar
testimony in regard to Pelopaeiis distillarms. He has opened
forty cells of this species and has always found the spiders alive.*
Thus we have, in the different species of this genus, the widest
variation in the habit of stinging the prey. Some kill almost
all of the spiders, others kill more than half, while yet others, it
is claimed, put up all their victims in a living but helpless con-
dition.

Our wasps did not share the habit of those observed in Erance,
in laying the egg upon the first spider placed in the cell. In-
deed we found that it was only after the nest was completely
provisioned that the egg was laid, on the abdomen of one of
the last spiders brought in. The importance which Fabre at-
taches to the early laying of the egg seems to us a little exagger-
ated as the difference in time in the two methods of procedure
cannot be enough to give much advantage either way. We
have often counted the number of journeys tliat a wasp makes
in an hour, and have found that it averages from twelve to
♦Bulletin Mosc, Tome XXL, 2, 1848, p. 248.

188 THE SOLITARY WASPS.

fifteen. At this rate the nest could be filled in about sixty
minutes, and even if it took two or three times as long the
change in the condition of the spiders would be insignificant.
If, in stocking her larder, Pelopaens had to hunt as long for her
spiders as Amnwphila does for her caterpillars, we might find
in the deposition of the egg upon the first one secured "the
happy arrangement" so much dwelt upon by M. Fabre. We
quote the folloT\dng notes kindly made for us by Mr. S. 1^. Dun-
ning, on P. cementarius.

Pelopaeus cementarius.
July 13, 1896.

"Four cells finished. IS'est formed on wall near ceiling in
home at Hartford, Ct.

"Cell IsTo. 1 contained pupa surrounded by a glutinous mem-
brane and the legs of spiders.

"Cell No. 2 contained pupa surrounded by glutinous mem-
brane but no spiders, legs or leavings of any kind.

"Cell 1^0. 3 contained a larva just ready to pupate and a few
remnants of legs of spiders.

"Cell !N^o. 4 contained a young larva 1-4 in. long and 11
medium sized spiders (oblong shaped and 3-8 in. long) of what
appeared to be two species of which 8 were black and 3 grayish.
Of these the legs of ten could be made to quiver but one was
apparently quite dead.

"A fifth cell, finished all excepting the entrance, contained
one spider which was easily made to quiver its legs. There was
no egg:'

After the egg is laid and the nest closed up the duties of the
mother are over and that cell and its contents are abandoned
to their fate. More mud is brought, more nests are built and
more egg's are laid, but further responsibility for her offspring
she knows not. If all goes well, in from two to three days, de-
pending on the temperature, the larva hatches and begins to eat
the spider to which it is attached, finishing the abdomen in one
day if it is of medium size. Quite commonly the larva eats

THE MUD-DAUBERS. 189

only tlie abdomens of the first four or five spiders that it attacks,
but after this it eats the cephalothorax and even the legs, of one
before passing to the next. Later on, it may return to the
harder parts that were neglected at first and devour them also,
finishing up, last of all, with any broken pieces of legs that may
have been overlooked. There are exceptions to this order, for
some larvse do not leave the first spider until the whole body is
consumed, but in all instances where the supply of food is
plentiful, many of the legs, and sometimes whole spiders are
left. Our study of the eating habits of these larvaB has led us
to the conclusion that they are not in the least fastidious as to
whether the food is hard or soft, fresh or dry. Their habit of
eating only the abdomens of the first spiders comes about from
the fact that when the abdomen is consumed it is broken from
the cephalothorax and in squirming around in search of an-
other piece they are likely to come into contact with another ab-*
domen. As they grow larger and stronger they eat the whole
spider at a sitting, be he alive or be he dead. Perfectly dry
spiders furnish as much proteid matter as the same number of
fresh ones. On several occasions when playing nurse-mother
to a number of growing larvae, which we kept in little glass
saucers, where we had not provided a large enough food supply
we made good the deficiency by adding a number of dead and
dry spiders that we had had on hand for some three weeks.
These were accepted by our infants, and were greedily devoured.
For from nine to fifteen days the larvte pass both days and
nights in eating. They consume, in that period, from five to
twenty spiders, the number being determined by their size. As
we are writing this, two larvse on our table are just entering the
cocoon stage. One of these has eaten six spiders, leaving a
few legs, while the other has devoured fourteen with the excep-
tion of half-a-dozen legs and the cephdothoraces of two, but in
the second case the spiders were yoimg and small, while in the
first they were nearly full grown, so that this one is really the
bigger glutton of the two. Whether the spiders used are large
or small depends primarily upon accident. The wasp takes
whatever she happens to run across, provided always that it is-

190 THE SOLITARY WASPS.

not too heavy for her to cai-ry nor too big to be pushed into her
cell. We have not a spider in our fauna that would not fall a
speedy victim to our Pelopaeus should she attack it. When ex-
perimenting on the mating habits of Attidae, some years ago,
we kept large numbers alive in our mating-boxes, and we found
the females of Phiddipus tripunctatus so vicious and powerful
that they had to be kept in solitary confinement to prevent their
killing the other spiders, and yet our slender mud-daubers used
these very females, even when they were full-grown. The
small and feeble spiders then, are not taken because they are
small and feeble but because they are so very abundant as to
make them a convenient source to draw from. All spider col-
lectore know that for each adult specimen taken in collecting
there are at least twenty that are immature. Among certain,
species it is almost impossible to get an adult specimen at certain
parts of the season although the immature forms are found on
every bush. In the latter part of August or early in Septem-
ber the female of A. riparia lays from five hundred to two
thousand eggs. The young spiders remain iu the nest through
the winter, and in the following May begin to spin their little
webs everywhere. Through June and July the mud-wasps on
their hunting expeditions meet them frequently and use them
freely. As they grow larger and scarcer other crops of young
and common spiders take their place. Interpolated all through
the season, we find the larger and rarer kinds in just about the
proportion that they bear to the smaller ones in nature.

Fabre's chapter on "Les Vivres du Pelopee" bears so strongly
upon our subject and is so interesting in itself that it seems well
to repeat some pgirts of it here. He says that so far as discover-
,ing the method of attack in Pelopaeus is concerned his efforts
have not been crowned with any great measure of success. He
has seen the wasp swoop down upon a spider, clasp it, and carry
it away, almost without pausing in 'her flight. Other hunters
alight on the ground, make their fastidious preparations sedate-
ly, and distribute the strokes of the sting with the calm deliber-
ation which a delicate operation demands. This one darts
down, seizes her victim and departs, something after the manner

THE MUD-DAUBEBS. 191

of Bembew. So rapid is tlie abduction that it may be presumed
that the mandibles and sting are only used while the wasp is
on the wing. This impetuous method, incom-patible with
learned surgery, explains to us, he thinks, even better than the
narrowness of her cells, the predilection of Pelopaeus for small
spiders. A larger and more powerful victim might put the
wasp in danger. The f aultiness of her art makes a weak victim
necessary to her. We must suspect that a spider so hastily and
carelessly taken, may be killed.

As a matter of fact careful and repeated scrutiny of the con-
tents of these cells, when the egg was not yet hatched, con-
firms these suspicions. There is never any trembling either
of palpi or tarsi, md In about ten days they decompose. This
then is what is stored in the cells of Pelopaeus, spidei's dead or
nearly dead. Is the learned art of paralyzing practiced by
Calicurgus upon the tarantula, which keeps it fresh for seven
weeks, unknown here? Have we here to deal, not with a deli-
cate operator who knows how to abolish movement without de-
stroying life, but with a brutal worker who kills for the sake of
rendering the victim immovable? Both the withered aspect
and the rapid deterioration of the victims bear witness that this
is the truth.

This, M. Fabre goes on to say, should not surprise us; later
we shall see wasps giving instant death by one stroke of the
sting with a science not less astonishing than that of the paral-
yzers. We shall see the motives which demand this and we
shall recognize under all its aspects, the profound anatomical
and physiological knowledge which a rational act would require
to rival the unconscious act of instinct. He then adds that he
cannot even suspect the cause which makes it necessary for
Pelopaeus to kill her victims but that he can easily understand
her logical method in turning to account these spiders, menaced
with early decomposition. In the first place the prey is mul-
tiplied in each cell. The piece actually attacked by the larva
is soon a disorganized mass, likely to decay speedily, but it is
small and is consumed before decomposition can advance, for

192 THE SOLITARY WASPS.

wlien a larva once attacks a spider it does not leave it for an-
other. Tte others tlien remain intact which, is enough to keep
them fresh during the short period of larval life. When, on
the contrary, the prey consists of a single large piece, it is nec-
essary that the organic life should be maintained, and a special
art must also be observed in eating it. It is well then that
Pelopaevs is inspired to take numerous small pieces. The egg,
moreover, is always placed on the first spider brought in,
whether the storing of the nest is completed within a few hours,
or whether, as in some cases, it occupies several days, and this
M. Fabre considers a very happy arrangement.

This account of the habits of Pelopaens and the explanation
offered for the several facts is exceedingly important, because
the French Pelopaei differ from ours at nearly every point.
Ours kill only about two-thirds of their victims, many of the
others being paralyzed so perfectly that they live for two or
three weeks. Again, ours, instead of placing the egg upon the
first spider, almost invariably lay it upon the last one brought in.
Another point of difference is that our larvae frequently eat
only a part of a spider at a time, returning to finish it later on,
a rash and reprehensible course of action of which their better-
taught French cousins are never gTiilty. When one comes to
compare the two sets of facts furnished by the two groups of
species the deductions which Fabre has drawn as to the import-
ance of the instincts of the French gToup are seen to be un-
founded. The American species violate nearly every principle
which he considers necessary to their existence, and yet they
flourish and multiply. It is just possible that our learned au-
thor has put a trifle too much philosophy into his interpretation
of the actions of these wasps. For our part we find nothing in
the actions of Pelopaens that needs to be explained — nothing
that is not well adapted to the conditions under which each
species works. The measure of praise or blame which we mete
out to these depredators is merely a way of saying whether we
would or would not follow their methods in provisioning our
houses and rearing our children. Perhaps we should always

THE MUD-DAUBERS. 193

use large spiders and should always liave them fresh, but it is
evident that tastes differ and the matter is so purely a subjective
affair that it will have to go unsettled. In any event whether
her victims be strong or feeble, old or young, big or little, fresh
or dry, they certainly serve admirably in enabling Pelopaeus
to rear brood after brood and to people the different parts of
the earth with abundant representatives of her kind.

If any conclusion can be drawn from our observations
it is that there is no importance to be attached to the number of
spiders stored, to whether they are large or small, to the plac-
ing of the egg on the first or on the last victim, nor even to the
state of the spiders, since those that are killed at once by the
stroke of the beautiful assassin serve their purpose just as well
as those that are paralyzed, and lie collapsed and powerless, all
unconscious of their approaching fate.

At the close of the period of alimentation the larva spins its
cocoon, which, light-colored at first, turns darker in the course
of a few days. Here it remains, perhaps for a few weeks, or
perhaps until the following spring. When it is ready to emerge
there exudes from its mouth a quantity of watery fluid which
serves to soften the cover of the cell so that it may easily gnaw
its way out. While watching a number of young wasps both
of the yellow and the blue species just as they were leaving the
nest, and even before their wings were ready for flight, we
noticed that when touched they at once attempted to sting.
This would seem to prove that the stinging habit is congenital
and instinctive.

We have made a number of experiments on different inverte-
brate animals to determine the effect of the venom of the wasps
w^hen injected into different parts of the body. Our first effort
was to discover whether animals could be killed by allowing
them to be stung several times at a point remote from the cen-
tral nervous system. For this, we took a small crayfish, two
and one-half inches long, and removed the first ambulatory
leg at the basal joint, and then held an individual of Polistef^

fusca in such a way that it thrust its sting into the exposed
13

194 THE SOLITARY WASPS.

end of the limb. Two stings were given at eack of wMcli the
crayfish straightened out violently. After a few seconds the
legs relaxed and their tips began to quiver just as we have seen
them do in spiders found in mud-nests. In a moment the cray-
fish became perfectly limp and remained lying either on the
dorsal or the ventral side, as it was placed. From eleven in the
morning until two in the afternoon, when it died, the maxi-
lipedes and ambulatory legs kept moving irregularly. The
sting could scarcely have reached a ganglion, so that the death
of the crayfish was due to the diffusion of the poison. This ex-
periment we repeated several times, substituting Pelopaeus
cementarius in place of Polistes fusca, and always with the
same results.

We next took a large spider, E. slrix, and breaking off the
second leg at the femur let the^ wasp sting it at the point of frac-
ture. This was at nine o'clock in the morning and the spider
remained limp and unable to move until five in the afternoon
when it partly recovered and began to move about with diffi-
culty. On the following day it still moved about slowly but
was far from appearing normal, and on the morning of the
third day it was dead. On the eighth day it was still plump
and in good condition although the sixth and seventh days had
been very hot, 90° Fahr.

On July fifteenth we let Polistes fusca sting a spider, E.
labyrinthea, in the middle of the upper surface of the abdo-
men. The spider remained in a motionless state with the legs
drawn up, until the next day, when it died. On July twenty-
fourth the spider was shrunken but the legs were still flexible
and the body soft.

We next let P. cementarius sting Marptusa fainiliaris^
twice at the spinnerets. The spider was paralyzed at once, all
the legs being limp although they quivered at the tips, but in
five minutes it recovered somewhat and was able to stagger
about. This continued for ten minutes when the wasp was al-
lowed to sting it again in the same place with the same imme-
diate result as before but this time there was no recovery and in

THE MUD-DAUBEBS. 195

tliirtj minutes the spider was dead. We repeated tMs experi-
ment with a large Thomisus, and with Dolomedes tenehrosus
and in both cases the stinging resulted in death at the end of
twenty hours. All of these spiders and many others were killed
by the general diffusion of the poison through the system and
not by any wounding of a ganglion. When we allowed a
considerable amount of venom to be injected death followed al-
most immediately but if a smaller amount was used the spider
lived a day or more.

One expeiiment was tried upon a large caterpillar, the sting
of our large hornet, Vespa maculata, being forced out and
pushed into the last segment, and some of the poison squeezed
into the wound. The effect of the venom was immediately
visible in the posterior third of the body. The anterior two-
thirds moved normally, dragging the end of the body along.
Perhaps this worked the poison forward for after a little all the
anterior parts became affected. An hour later the caterpillar
seemed slightly better, but on the next day it was so much af-
fected that it could not turn over when placed on its back, mov-
ing only when stimulated. On the third day it was alive but
very sluggish, moving slowly when touched, and on the fourth
day it died. This was on the fourth of July. On the seventh
it was still soft and in good condition, but by the eleventh it
was quite dry.

A large number of spiders that were killed in our experi-
ments were kept that we might note the time at which decom-
position began. We found that on the average they kept fresh
for ten or twelve days after death. We had only one which
began to decompose as early as the ninth day, and even in this
case the spider was in what a wasp larva would have considered
an edible state three or four days longer. All of our experi-
ments were in complete agreement with the condition of things
found in the nests, where many of the spiders were alive when
first stored but died from day to day, and whether dead or alive,
plump or dry, were eaten eagerly and with apparent relish.

The following table shows for eleven nests, of which we pre-

196

THE SOLITARY WASPS.

served tlie contents, the rate at wliicli the spiders died. In all
these instances the nest had not yet been closed, as in niTmbers
four and eleven, or if closed, the egg had not hatched, show-
ing that the spiders could not have been stored more than two
or three days. Of eighty-four spiders forty-three died in from
two to five days while only fifteen lived from thirty to forty
days.

Table No. II. Showing the length of life of sjnders found in wasp

nests.

Condi-
tion

of the

spiders
when

found.

No. of days that the spiders lived after nest
was opened.

Remarks.

d

CD
<s

<

2

3

4

7
9

"'

2
2

20

5

9

1

2

12

7

3

"

3
6

8
1

1

9

2
2

10

1

2

12

1
1

1
3

13

1

14

1

15

2

1

3

16

2

3

20

1

25
1

1

29
2

2

30
3

7

31
1

1

32

3
3

35
1

1

36

1
1

38

31

1

40

^1
1

11
2
3
4
5
6
7
8
9
10
11

7

12
7

11
1
7
2
3
2
12
11

6

12

12

3

13

6

3

6

15

5

3

2
2

7
2

9

Egg not hatched.

Egg not hatched.

Egg not hatched.

Nest not closed.

Spider fresh
looking.
Egg not hatched.

Egg not hatched.

Egg not hatched.

Egg not hatched.

Egg not hatched.

Nest not closed,
Egg not laid.

Total

75

84

1 Nest number 1 was Pelopaeus cementarius,

"This spider was so slightly injured that it moved about and moulted once.

* Very little hurt, moved freely.

Eabre has found the meonbers of the genus Pelopaeus ©xceed-
ingly iminitelHgeaiit and absolutely lacking in rational disK^em-
ment,* but ervideoioe of quite another character is found in some

♦Aberrations de 1' Instinct, Souvenirs Entomologiques, Quatri&me
Serie, chap. III.

THE MUD-DAUBERS. 197

experunents made on a miid-daiiber mainy years ago by Mr. P. H.
Gosse, from wlLoan we quote tJie following:*

"June 30. I watched with much interest the proceedings of a Dau-
ber in building her mud-cells; it is a pretty species (Pelopaeus flavipes).
She has chosen the ceiling of a cupboard in my sitting room, where,
previously to my observing her, she had made one cell and the half of
another parallel to it; the former was closed, the latter had got its
contents of spiders, and only wanted closing. Such was the status quo.
**********

She then flew off and returned with a similar load, which she ap-
plied upon the last to make it thicker. When she was gone the third
time, in order to observe her behavior, I thrust the head of a pin
through the newly laid mortar, opening a hole into the cell. On her
return, she at once perceived the hole, and deposited her lump upon*
it, spreading it about as before. I plaj'ed her the same trick several
times, at all of which her proceedings were the same, save that at
length she seemed to become very angry and endeavored to catch the
house flies that were flying and crawling near. I have no doubt that
she suspected them of having a hand in it. At all events, rhe jumped
at them very snappishly Avhenever they came near, and sometimes
even with the load in her mouth, but I did not see that she caught
one. Once, too, a large Ichneumon Avas lurking about, at whom she
fiercely flew, and I think they had a short struggle. At times she
would linger at a little distance, after depositing her load, apparently
hoping to catch the insidious house-breaker, 'in the manner' as law-
yers say.

"At length I broke off a large piece from the side and bottom of the
old part, exposing the spiders to view; this, however, she speedily
built up as before, at two or three loads, adding to the standing part
all around the hole, and not at one side only. After this I did not put
her industry to the task any more, but suffered her to finish her work,
w^hich she did by adding another layer or two to the end. I, however,
made a hole in the first cell, which was quite hard and dry, to see if
she would observe it, which she did at Once, and clapped her load of
mortar o*^ it. I noticed that while working-, though the wings w^ere
closed incumbently, she kept up a shrill buzz, like that of a bee when
held in the fingers; her antennae, which were usually "irried nearly
straight, were during the plastering furled up and contiT^nnlly vibra+-
ing and moving on the surface of the work, evidently trying it by

*Letters from Alabama on Natural History, London, 1859, pp. 239-
241.

198 THE SOLITARY WASPS.

touch, which, seemed to me adverse to the theory that calls the anten-
nae 'ears.' In seeking her materials, she was gone often more, never
less than a minute, and always brought a lump similar in appearance,
which was invariably carried in the jaws, without any aid from the
feet.

"The Dauber built another cell today, on the other side of the first,
which is now therefore in the middle. I again pestered her by sticking
a small tin tack in the newly laid mud, just where she would have to
deposit the next load. When she came, she appeared quite bothered;
she ran back and forward, and round a<nd round over the cells for
some time with the mud in her jaws, as if at a loss what to do in so
novel in exigency. It was a different case from the former; a hole
could be stopped up, but here was an intruding substance just where
she wanted to deposit; should she lay it on, the incumbrance would
be more firmly imbedded; should she place it elsewhere, it would be
wasted, not being needed, or perhaps be positively injurious; should
she attempt to remove the evil, her raouth M^as occupied, and she was
unwilling to lose her burden. At length, however, as the least of the
evils, she seized the tack w^ith her jaws and drew it out, dropping her
mud in the effort. When she was away the next time, I bundled up
a worsted thread, and pressed it on the soft work, which presented a
still more serious obstacle, as she could seize only a small part of it
which would yield without coming away; however, by tak'ng hold of
several parts of it successively and tugging at them for a long time
and by walking round and round with it in her mouth, she at length
got it out. These instances of sagacity and perseverance greatly
pleased me. After laying on the load, she always cleans her antennae
with her fore feet, and her feet with her jaws; on arriving she never
alights at the nest, but always on the inside of the cupboard-front
and crawls along the ceiling to it."

Summary.
Our Pelopaetis, then, builds her nests of plain mud, in shel-
tered places. The food-supply of the larva consists of a vari-
able numbers of spiders, a few if large ones are taken, many if
they are small. Size, sex, and kind are unimportant, the wasp
showing the greatest variation in these matters, probably, in-
deed, taking the first thing that comes in her way. If the
weather is fine the work of building and | rovisioning is com-
pleted in one day. Her skill in the use of the sting is all that is
required for her purpose which is rather to overcome any resist-

THE MUD-DA UBERS. 199

ance that she may encounter than to paralyze the spider and
thus keep it fresh. To her it is a matter of indifference whether
the spiders are killed or paralyzed, and either result may fol-
low. The examination of cells recently provisioned shows that
while most of the spiders are dead, many of them, although
motionless, are alive and will respond to stimulation by a quiv-
ering of the tips of the legs. These living spiders die from
day to day, the death rate depending upon the amount of poison
that has been injected. It is probable that the spiders are
usually stung in the under side of the cephalothorax. We base
this opinion upon what we ourselves have seen and also upon
the fact that many of the Pelopaei take spiders of the genus
Gasteracantha, in which this is the only part soft enough to be
penetrated, all the rest of the spider being enclosed in homy
plates; and it is commonly the fact that among the solitary
wasps all the members of a group sting their victims in the same
way.

200 THE SOLITARY WASPS.

CHAPTEE XV.

EXTRACTS FROM MARCHAL'S MONOGRAPH ON CERCERIS

ORNATA.

The memoir of Paul Marchal on Cerceris ornata* contains
so much that is of interest that a series of short quotations from
it would quite fail to give an idea of the thoroughness of the
work upon which it is based and of the importance of the re-
sults. We therefore take the liberty of transcribing freely a
considerable part of the paper.

The nest of the wasp consists of a tortuous gallery from
which lead a number of rounded cells. In each of these is de-
posited an egg with enough bees of the genus Halyctiis to nour-
ish it through the larval stage. The provisioning of one cell
is completed before that of another is begun, so that in a single
nest there may be found one cell partly provisioned, one with
an egg and others in different stages. The egg is placed diago-
nally on the ventral face of the thorax. A single cell contains
a variable number of victims — some seven or eight, others four
or five. Probably those of a small number are destined for the
males. The species of Halyctus used are numerous, and male
bees are often found among the victims, some cells having noth-
ing else.

iCerceris ornata is one of those wasps that are not disturbed
by artificial conditions. When placed with a bee under a bell-
glass her method may be studied in detail. It is only necessary
to have patience — in a quarter or half an hour she comes near
Halyctus and engages in combat. If one has laid in a sufficient

*Etude sur I'lnstinct du Cerceris ornata. Archives de Zoologie Exper-
imentale et Geai6rale, Deuxieme Serie, Tome. Cinqui6me, 1887.

MARCHAL ON CERCERIS ORNATA. 201

supply of bees lie may continue to assist, as long as lie wishes, at
the manoeuvre of Cerceris. It is not even necessary to take the
wasp with her victim; it is enough to shut in together an Halyc-
tus and a female Cerceris, always with the condition that the
latter has been captured while hunting. "Five successive-
times," says Marchal, "I saw Cerceris return to the assault and
recommence the same manoeuvi-e on the unhappy bee. To
speak truly the immediate result obtained by this succession of
operations did not appear to me to ccn-espond with the energy
employed, and after the fifth operation the immovability was-
scarcely gTeater than after the first. Moreover the one which
received the assault five times, taken at two o'clock, still moved
its legs the next morning after the abdomen was excited; this
is precisely what resulted from a single operation."

The instinctive act of Cerceris, then, may be considered a
reflex due to the sight of the bee and able to be accomplished
an indefinite number of times so long as the wasp is in chase.

At the moment of capture Cerceris seizes the bee brusquely,.
clasping the anterior part of the body with her mandibles. Her
recurved abdomen darts the sting into the neck at the articula-
tion of the head and thorax, the stroke being given vigorously
as though it were of capital importance. For a few moments
the two combatants roll on the gTOund; one or two quick strokes
are given under the thorax, principally between the prothorax
and the mesothorax, and the bee becomes motionless; then
Cef'ceris holds her victim face to face with her, looks at it a few
seconds, and turns it around so as to bring the neck opposite her
mandibles. The bee being thiis adjusted the wasp proceeds tO'
dig at the nape of the neck, squeezing it for from two to four
minutes. This process is usually performed within the nest,
and it is noticeable that Cerceris, after the malaxation, does not
drag her bee by an antenna as she would do if the operation
usually preceded the entrance into her hole. On the other
hand the wasp sometimes gives the strokes with her sting and
then, not proceeding to malaxation, at once begins to drag the-
bee as if seeking to regain the nest.

202 THE SOLITARY WASPS.

Marclial does not agree witli Fabre in his belief tbat wasps
are endowed not only witb tools but witb tlie method of using
them, the gift being original, perfect from the beginning, not
modified by past or future. The action of Cerceris does not
imply any mysterious science. She runs the end of her abdo-
men along the under surface of the thorax of the bee and stings
at the division of the segments — that is at the points where the
sting can enter. The order in which the strokes are given is
very variable, and if the neck is protected by gum-arabic, so
that it is impervdous, the stings between the pro- and mesothorax
give just the same result. All that is necessary is that the
sting shall reach the line of nervous matter that runs along the
ventral face of the thorax. As a matter of fact it does not
touch the ganglia, but enters just half way between them. The
distance is small and the poison quickly reaches the nervous
centers. (PI. X. fig. 4.)

The order in which the stings are given is variable. We
may consider that there are four classes:

In class A. the sting is given:

1st, at the neck.

2nd, at the articulation of the prothorax and the mesothorax.

3rd, at the neck.
. In class B. it is given:

1st, at the neck.

2nd, at the articulation of the prothorax and the mesothorax.

In class C. it is given:

1st, at the neck.

2nd, at the articulation of the prothorax and the mesothorax.

3rd, behind, toward the origin of the abdomen.

In class D. it is very probably given in a considerr.ble num-
ber of cases, either only in the articulation o:^ the prothorax and
the mesothorax, or only in the neck.

Cerceris is far from using the exquisite method of malaxa-
"tion followed by Sphex, as described by Fabre. She is on the
contraiy, quite brutal. She pricks and squeezes the neck of the

M ABC HAL ON CERCEBIS ORNATA. 203

victim and tlien licks off tlie juice that exudes. All the bees
that have undergone this operation have the neck cut, some on
the median line, some on both sides. The supposition that Cer-
ceris proceeds differently with the bees which are destined to
feed the larvae, perhaps not malaxing them at all, or only deli-
cately, proves to be incorrect, since half the bees that were
taken from nests showed marks of being cut. The other half,
upon which no sign of a wound was visible, had probably re-
ceived lesions which resulted in death after a brief delay. Of
five bees taken from nests where the egg had not yet hatched
three days), only one responded to stimulation of the electric
three days), only one responded to stimulation of the electric
current by flexing the anterior legs at the moment that it was
applied, the others giving no reaction. Moreover of three
taken from a nest not yet fully provisioned one gave no response
to the electric current.

These facts show that the instinct of the Sphecidae may well
have been derived from the struggle for existence. If Cerceris
paralyzes Halyctus it is partly in her personal interest, that she
may perform the malaxation at her ease. Does not the instinct
of all these wasps to paralyze their prey for the benefit of beings
which they do not know, since they are still in the egg, — which
they can never know, since they will die before the young hatch
out; which, by a series of well ordered acts assures the propa-
gation of the race without the insect having the least knowl-
edge of the aim to be reached ; does not this instinct appear bet-
ter than any other so to unite all the conditions that it will
serve for an argument of the partisans of the supernatural in
!N'ature? and yet we see that in the actual case the instinct can
be brought back to the most natural thing in the world — indi-
vidual interest and preservation of the individual. It may be
that other original causes have presided over the evolution of
the instincts of the solitary wasps, but while we wait for new
facts, to suppose such causes would be to make a useless hypoth-
«sis.

204 THE SOLITARY WASPS.

State of the Victims.

Wlien Cerceris abandons her victim, after malaxation, it
presents disordered movements in all its members; incapable of
taking a step, it rolls on its back when one sets it on its legs;
the mandibles are immovable and the antennae nearly so. Spon-
taneous movement ceases about ten hours after malaxation, but
even now a light excitation of the abdomen leads to a moder-
ately lively reaction in the posterior legs.

During all the time that this partial paralysis lasts the tarsi'
are animated with movements of oscillation which are quite
rapid at the beginning and which diminish at the end. These
oscillations last, usually, longer in the posterior legs than in the-
anterior. The nervous center which presides over their move-
ments is, in fact, further from the point pricked by the sting.

Out of eight individuals, seven no longer presented the least
movement, either spontaneous or provoked, twenty-four hours
(and less than that for some of them), after the operation. The
other one presented no movement forty-eight hours after. It
is rare that the movements persist so long as this. Even by elec-
tricity it often is impossible, in less than twelve hours after the-
cessation of movement, to bring back the least trace of irrita-
bility. Thus the operation performed by Cerceris has the
effect of plunging the victim, after a brief delay, into a state
absolutely comparable with death.

l^ow what is the rdle of the sting and what the role of the
malaxation?

To learn this some bees were taken from Cerceris as soon as
they had been stung, at which point they fall into a state of
complete immovability, only the extremity of the abdomen
being, from time to time, lightly agitated. This state lasts onlj
a few instants, scarcely a minute ; soon the movements of oscilla-
tion begin, appearing firet in the posterior legs; some seconds-
later the intermediate tarsi begin to move; then the anterior
tarsi; a little later a jerky movement of the anterior legs and of"

MABCHAL ON CERCERIS OENATA. 205

tlie antennae announces the reawakening, and in about three
minutes the posterior legs move about in a disordered way.
The insect then begins to come out of its general numbness and
finds itself in just about the same state as a bee which has just
been subjected to malaxation. Xow since malaxation lasts just
three minutes it would seem that this process adds nothing to
the sting, but it is only necessary to compare a series of bees
which have been subjected to it with one w^hich has not, to be
convinced that this is not true.

Half an hour after the operation the bee which has not had
malaxation has recovered to the point of vibrating its wings rap-
idly; its leg's move quickly, its antennae are mobile, and the in-
sect presents its ordinary appearance, even taking some steps but
soon rolling on its back. This state of relief from numbness
progresses for three hours. In two hours it turns its Lead right
and left, moves its antennae, even tries to bite with its mandi-
bles. These movements are not automatic but voluntary. It
tries to fly but cannot leave the earth.

In the meantime in the bee that was submitted to malaxation
the state of torpor pei-sists and only changes to become more
complete. The movements show a suppression of all that is
voluntary. The only trace of co-ordination is that it frequently
strokes its flanks and its legs with the posterior legs as if to rub
off pollen. This suppression of the will is the result not of the
compression of the neck but of the loss of nourishing juices re-
sulting from the hemorrhage of the great dorsal vessel.

Eeturning to the bee that has not been malaxed, we find
that the movements persist with a certain intensity up to the
fourth hour and then diminish and finally disappear. The table
shows that movement persists much longer ^n this class than in
the other.

Out of eight bees that were subjected to malaxation after
stinging :

7 ceased to move the first day after operation.

1 ceased to move the second day after operation. j

206 THE SOLITARY WASPS.

Out of eight bees tliat were subjected to stinging without
malaxation :

1 ceased to move the first day.

2 ceased to move the second day.

3 ceased to move the third day.
1 ceased to move the sixth day.

1 ceased to move the twelfth day.

In one case in which there was no malaxation the state of
paralysis was truly remarkable, quite comparable to that which
M. Fabre has described with the Curculionidae of another
Cerceris: The details are as follows:

The third day after the sting the oscillations of the tarsi per-
sisted in a constant manner; the posterior legs reacted strongly
whenever one excited the abdomen; the antennae were easily ex-
cited. The fourth and fifth days gave the same symptoms.

On the sixth day fseces were passed.

On the seventh the oscillations persisted., the antennae being
always half raised when the abdomen was excited; the posterior
legs did not react, but the abdominal extremity was recurved.
Faeces were passed.

On the eighth, ninth, tenth, and eleventh days the oscillations
of the tarsi persisted, rhythmically, with strong accentuation.

On the twelfth day in the morning, the oscillations of the in-
termediate tarsi were plainly much weaker than in the anterior
tarsi, while those of the posterior tarsi persisted with a good deal
of vigor. By evening the oscillations of the tarsi had ceased.

On the eighteenth day the tarsi broke off showing that desic-
cation had begun. Cerceris, then, can paralyze its prey and
can plunge it into a state of torpor which lasts fifteen days,
giving the larva fresh and living food.

An effort was made to get malaxation without stinging, but
Cerceris would not go on to this part of the treatment until
the bee had been rendered motionless by the sting. When the
sting was cut off, she used the abdomen as if stinging, trying
again and again as this failed to produce the desired result, and
finally letting the bee escape. The real object of the sting,

MABCHAL ON CERCERIS ORNATA. 207

then, is to render the bee motionless so that it can be conven-
iently handled.

Conclusions.

1. The effect of the sting is to produce inhibition; this per-
mits Cerceris easily to carry the bee into her hole.

2. Inhibition ceases, but the nervous system has been so in-
jured that the insect does not recover. Still motion may per-
sist for a long time if there has been no malaxation.

2. Malaxation by the effusion of blood which it produces,,
and also by the lesion of the nervous chain, strikes a fatal blow
at voluntary movement, and leads to the suppression of animal
life in about twenty-four hours.

State of Preservation of Yietims.

Fabre has preserved the beetles of a Cerceris for more than
a month without their losing their freshness. The crickets of the^
yellow-winged SpJiex were preserved for a month and a half,
and the victims of another Spliex for two or three weeks. Move-
ments, either voluntary or provoked by electricity, betrayed the
presence of life. Fabre's conclusions are as follows:

1. Vegetative life is preserved for several weeks after a sting
from one of these Sphecidae.

2. The preser\"ation of the vegetative life is necessary to the
larva.

Are these conclusions applicable to Cerceris ornata'i The
bees which have been stung and malaxed, when put into paper-
cornets, dried up at once. The muscles were entirely dry, like
parchment, in five or six days.

Those which had been only stung did not dry so quickly, and
sometimes eight or ten days after movement ceased the muscles
were still easily dissociable. These results demonstrate that the
result of the complete operation is speedy death.

The bees which were taken from nests never dried up so
quickly as those which were operated on artificially, being killed

208

THE SOLITARY WASPS.

by cHoroform, bj pricking' tliem between the pro- and meso-
tborax, by decapitation or other means.

Resume of Ohservations on Fifteen Nests.

When the bees are taken from freshly provisioned nests be-
fore the egg has hatched the muscles may remain fresh until
the eighth day or even to the ninth or longer, but in some cases,
all other things being equal, dryness appears on the fifth day,
and is complete on the seventh. Out of thirteen cases four were
completely dry on the eighth day. The bees which were caught
and killed began to dry at once and dryness was usually com-
plete on the fifth day.

Andrenae, which are sometimes found in the nests, were
given to Cerceris instead of Halyctvs, wdth the result that they
always dried more rapidly (in four or five days.)

Finally the contents of each of some freshly provisioned nests
have been separated into two parts, one of which was submitted
for five minutes to the vapor of chloroform in a tightly corked
flask while the other remained intact. Those that had been
chloroformed did not dry more quickly than the others. In
"^ome cases the chloroformed ones were still fresh when the ,
jthers were perfectly dry. This experiment goes to show that
a good part of the bees are really dead. One may object that
they are in a state of numbness analogous to hibernation, and
that as they are scarcely breathing they are not affected by chlo-
roform. Possibly this objection is well founded but it is none
the less true that this state of numbness is of very short dura-
tion, sometimes scarcely perceptible.

The bees, then, are not preserved for a month and a half.
They die in ten days or even in a shorter time.

Bees are sometimes found in the cell occupied by the larva of
Cerceris, which have plainly been dead a long time although
they appear intact and show no lesion attributable to the larva.
The length of time that it takes the larva to develop is not
known. The eggs which have been found fastened to bees have
not hatched or have hatched and then died. One of these eggs

MARC HAL ON CERCERIS ORNATA. 209

hatclied on tlie fourth day. At other times rather big larvae
have been kept for three or four days before they spun their
cocoons. Thus we have a minimum of eight days for develop-
ment, and we have seen that the bees sometimes dry up in five
days. It is then almost certain that the larvae of Cerceris often
have to eat bees which are already dead. It would be interest-
ing to see if, as the instinct of the wasp becomes more perfect,
the time necessary for the development of the larva becomes
longer, as Darwin would doubtless have thought probable.

As has been seen, we are far from finding such masters in the
art of paralyzing as Fabre did. Moreover, there is much varia-
tion both in method and in results. Are these signs of perfection
of instinct? 'No. Cerceris ornata, from the point of view of in-
stinct, seems to be a transitory type between the butcher wasp
and the paralyzing wasp (speaking, now, only of instinct, and
not of the line of descent.) The butcher wasp kills and cuts
up its victim, eating what it wants and carrying the rest to
the larva. The paralyzing wasp is the one that has no individ-
ual interest in its prey, as Spheco or Ammophila. Between
these types we may put Cerceris ornata, and Chlorion com-
pressimi which provisions its nest with cockroaches from which
the wings and legs have been cut off, certain Pompilidae,
which, according to Goureau, cut the legs from the spiders
which they capture, and PhilantJius apivorus, which, according
to Fabre, squeezes the bee to make it give up its honey (after
paralyzing it), and many other cases which show various shades
of evolution of instinct.

Errors of Instinct.

While Cerceris was away hunting, some dry sand was thrown
into the nest and the entrance was then stopped with damp sand.
She returned laden with prey, and seeing herself forced to re-
sume the profession of a miner, abandoned her victim, cleared
the entrance, penetrated within, came out again, and flew off in
14

210 THE SOLITARY WASPS.

search of new prey.* After two successive trips slie penetrated
a third time into her dwelling and began to reject the dry sand
which had been thrown in. In the midst of this sand was a
bee. It was evident that in one of the trips that we had seen
her maie she could not reach directly to the cell which she
was provisioning and dropped the victim at the place where she
had to stop. Presently the wasp flew away. The hours passed
on, and she returned without a bee, entered and threw out the
other one which she now considered an encumbering object.
Thus of two victims which were procured with great trouble,
one was abandoned on the threshold, and the other was dropped
half way in — neither served as food for larvae. What of that?
Cereeris had given the sting — that was enough.

At another time a nest, one of the cells of which was not en-
tirely provisioned, was destroyed at evening. On the next
morning Cereeris brought a newly stung bee and placed it in
the hole. On the following day she came again, charged with
prey, and dropped her bee which rolled to the bottom of the ex-
cavation. She had not brought the full number for provision-
ing the nest. Instinct commanded her to bring them, and she
obeyed, but not knowing where to put them, let them fall.

These things show the astonishing force with which a habit,
once acquired, fixes itself in the brain of an insect, and is trans-
mitted from generation to generation. It is precisely this which
constitutes instinct and it is difficult to see how these facts can,
as some authors would wish, make us believe that insects are
incapable of acquiring habits, which, growing stronger and
stronger, are substituted little by little for old ones. In a word,
it is difficult to see how any one can find in them any proof of
immutability of instinct.

*Our I*, punctatus, under similar circumstances, dropped the bee
while she cleared the entrance but then picked it up and took it in.

THE SENSE OF DIRECTION IN WASPS. 211

CHAPTEK XYI.

ON THE SENSE OF DIRECTION IN WASPS.

PI. IX., fig. 5; PL XII., figs. 1—4.

Mucli of a Mglily speculative cliaraeter lias been written upon
tlie lioming faculty, and, in lieu of a better explanation of cer-
tain facts, animals and certain tribes of men have been supposed
to possess a sense of direction tbat was so far independent of
experience and instruction as to be instinctive, and, consequent-
ly, to a very bigb degree unerring. Mr. Darwin when con-
sidering this matter in relation to bees and wasps, suggested tbat
tbey kept their course by a process of dead reckoning, every
turn tbat was taken in their excursions being noted and remem-
bered, but Fabre, after testing this suggestion by experiments,
concluded that the facts could not be explained in this way. Sir
John Lubbock and Romanes have also made interesting observa-
tions on this subject which tend to confirm Pabre.

In a former paper, on the social wasps, we narrated a number
of experiments which we had made to determine whether wasps
could find their way back to the nest when they had been car-
ried to a distance. These experiments served to show that the
insects returned to their home unless they had been taken so far
away that the over-looked country, as they circled higher and
higher, presented no familiar object to their view. With the
solitary wasps we have attacked the problem from the other end.
In our earlier studies we observed what they did in attempting
to return to the nest; in the later ones we have watched them
when, after making a nest, they prepared to leave it to go out
into the fields or woods in search of food or prey, thinking that
the procedure of different species under these circumstances
would afford a clue to the faculty upon which they depended to

212 THE SOLITARY WASPS.

find tlieir way about. If they were furnislied with an innate
sense of direction tliey would not need to make a study of tlie
locality of the nest in order to find the way back, but if they
were without this sense it would be only common prudence to
take a good account of their bearings before going far afield.
The minute and careful study of such small matters may not
be so pleasant as philosophising about them but it is sometimes
more profitable, and we may truthfully say that we have found
the investigation of these details of more interest than the cor-
responding affairs in human life.

The sight of a bee or a wasp returning to its home, without
hesitation or uncertainty, from some far distant spot is, indeed,
marvellous. When we saw our first Ammopliila perform this
feat we were filled with wonder. How was it possible for her
to hunt for hours, in all directions, far and wide, and then re-
turn in a direct line to a nest which had been so carefully cov-
ered over that every trace of its existence was obliterated?
Looked at in this way it is indeed a mysterious process, best ac-
counted for by giving her a sixth or a seventh sense — a sense of
direction.

This, however, is not quite fair to her ladyship's intelligence,
as a better acquaintance with her would prove. In reading
much of the popular natural history of the day one might sup-
pose that the insects seen flying about on a summer's day were
a part of some great throng which is ever moving onward, those
that are here today being replaced by a new set on the morrow.
Except during certain seasons the exact opposite of this is true.
The flying things about us abide in the same locality and are
the inhabitants of a fairly restricted area. The garden in which
we worked was, to a large extent, the home of a limited number
of certain species of wasps that had resided there from birth or
having found the place accidentally, had settled there perma-
nently. To make this matter clear let us suppose the case of
an individual of A. urnaria. In June she spent her time in
sipping nectar from the onion flowers or from the sorrel that
grew on the border of the garden. In July came the days of

THE SENSE OF DIRECTION IN WASPS. 213

her courtslup and lioneymoon, and these too were passed in
going from flower to flower, from one part of the garden to an-
other. Many a day we have followed her when she flew from
blossom to blossom along a row of bean plants, turning, when
she reached the end, and wending her way leisurely back along
the next row. Then oomes a day when we see her running
orer the ground and looking carefully under the weeds for a
good nesting-place. At last a spot is selected and she begins
to dig, but two or three times before the work is completed she
goes away for a short flight. "When it is done, and covered
over, she flies away, but returns again and again within the next
few hours, to look at the spot and, perhaps, to make some Httle
alteration in her arrangements. From this time on, until the
caterpillars are slored and the egg laid, she visits her nest sev-
eral times a day, so that she becomes perfectly familiar with the
neighborhood, and it is not surprising, after all, that she is able
to carry her prey from any point in her territory in a nearly di-
rect line to her hole — we say nearly direct, for there was almost
invariably some slight mistake in the direction which made a
little looking about necessary before the exact spot was found.

After days passed in flying about the garden — going up Bean
Street and down Onion Avenue, time and time again — one
would think that any formal study of the precise locality of a
nest might be omitted, but it was not so with our wasps. They
made repeated and detailed studies of the surroundings of their
nests. Moreover, when their prey was laid down for a moment
on the way home, they felt the necessity of noting the place
carefully before leaving it.

Of the species that catch their prey before making the nest
we have good examples in Pompilus quinquenotatus, the torna-
do wasp, and fuscipennis, the Pompilus with the red girdle.

The tornado wasp may make her nest anywhere from one to
ten feet from the spot on which she has. deposited her spider,
while fuscipennis never goes more than fourteen inches away.
During the process of excavation both of these wasps pay sev-
eral visits to the spider and frequently they have difficulty in

214 THE SOLITARY WASPS.

finding it. As an example of this kind of trouble we give a dia-
gram (PL Xn., fig. 5), of the course followed by an individual
of fuscipennis, after she had finished her nest, in trying to find
her spider and, in bringing it home. This and the other similar
diagrams that are given, are reductions of large tracings that
were made on the spot. Although not absolutely correct they
are exact enough for all practical purposes. Whenever there
is an error it is necessarily in the direction of making the path
pursued by the wasp appear shorter and less complex than it
really was. The individual in question had placed her spider
on a cucumber vine not far from the ground. It was not hid-
den by leaves but was fully exposed to view. The nest was
only eight inches away but when it was finished and the wasp
went to bring the spider, she found it only after a search of
three minutes, and then when she went back to the nest she at
first passed to one side and went some inches beyond and had to
retrace her steps.

We watched ten different individuals of this species and every
one of them had trouble in remembering the path between the
nest and the spider. Once we caught one that had just hung up
her spider, and released her, almost immediately, on the same
spot. She hunted about in the wildest way for fifteen minutes,
going further and further away, and would never have found
her treasure if we had not helped her. Such an amount of run-
ning and flying, here, there, and everywhere, would be incom-
prehensible in an animal endowed with an innate sense of direc-
tion, and we fear that the wasps must surrender to the bees or
the cats all claim to such distinction. Certainly we have discov-
ered no trace of it in the forty-five species that we have studied.

The best evidence that wasps depend upon a knowledge of
the place in returning to their nests, is given by the pains that
they take to acquire that knowledge. When Sphex ichneumo-
nea was ready to dig her nest she had great difficulty in find-
ing a place that suited her. Many a spot was merely looked at
and passed by, while others, that seemed more attractive, were
left after they had been excavated for a little way. At last,

THE SENSE OF DIRECTION IN WASPS. 215

the nest dug, she was ready to go out and seek for her store of
provision and now came a most thorough and systematic study
of the surroundings. The nests that had been partly made and
then deserted had been left without any circling. Evidently
she was conscious of the difference and meant, now, to take all
necessaiy precautions against losing her way. She flew in and
out among the plants first in narrow circles near the surface of
the ground, and now in wider and wider ones as she rose higher
in the air, until at last she took a straight line and disappeared
in the distance. The diagram (PI. XII., fig. 1) gives a tracing
of her first study preparatory to departure. Yery often after
one thorough study of the topography of her home has been
made, a wasp goes away a second time with much less circling
or with none at all. The second diagram (PI. XII., fig. 2) gives
a fair illustration of one of these more hasty departures. To
some philosopher sitting in his study and reading learned works
upon instinct and reason, this may seem all foolishness, and cer-
tainly if he prefers to believe that the wasp is endowed with a
sense of direction, and that all this flying here, and circling
there, has nothing to do with her method of finding her way,
he is at liberty to do so, even if this does leave a rather large un-
explained residuum.

If the examination of the objects about the nest makes no
impression upon the wasp, or if it is not remembered, she ought
not to be inconvenienced nor thrown off her track when weeds
and stones are removed and the surface of the ground is
Fmoothed over; but this is just what happens. Aporiis fasciatus
entirely lost her way when we broke off the leaf that covered
her nest, but found it, without trouble, when the missing object
was replaced. All of the species of Cei'ceris were extremely
annoyed if we placed any new object near their nesting-places.
Our Ammophila refused to make use of her burrow after we
had drawn some deep lines in the dust before it. The same an-
noyance is exhibited when there is any change made near the
spot upon which the prey of the wasp, whatever it may be, is
deposited temporarily. We learned from experience how im-

216 THE SOLITARY WASPS.

portant it was not to disarrange the grass or plants on sucli oc-
casions. Tlie wasps are in many cases so prudent as to conceal
their booty among the leaves and this made it very inconvenient
to keep our eyes upon the captured prey, as was quite necessary
if we wished to follow it on its travels. To avoid the discom-
fort of lying on the ground or of twisting the neck at some im-
possible angle for half an hour at a time, we sometimes gently
moved the intercepting objects to one side, but even such a
slight change cost us dear in time and patience as it threw the
wasp out of her bearings and made it difficult for her to recover
her treasure. We recall one exceedingly warm day in Septem-
ber when we were delayed in this way for forty minutes, when
she would have seized the spider and gone on her way without
a pause had we not interfered.

Very often the wind would shake the plant so that the spider
or caterpillar would fall to the ground. Under these circum-
stances the wasp was not at all disconcerted but, on not finding
her prey where she had left it, dropped at once to where it was
lying. This is probably only an extension of their ordinary
habits, A wasp that takes spiders learns to follow them as they
drop from the web on being disturbed. In this they are evi-
dently guided by sight, but perhaps they are also aided by the
sense of smell under other conditions, to the extent, at least,
of recognizing the place upon which their prey has lain. With
so much to build upon it is easy to see how natural selection
may have perfected the habit. We are delaying a long time
over details but we feel that to invoke an unknown sense is only
permissible after a careful study of the daily life of the animals
in question has left the problem unsolved.

Among the wasps that first make the nest and then provision
the larder, Astata hicolor is one of the most interesting. She
makes a permanent abiding-place and probably uses it until all
of her eggs are laid. It is evident that since she comes and
goes many times during the several weeks of her occupation she
does not need to make a prolonged study of the environment at
every departure. Her first survey, just after the nest is com-

THE SENSE OF DIRECTION IN WASPS. 217

pleted, is most thorongli, and, as a usual tMng, wlien she first
comes out on eacli succeeding morning, she reviews the situa-
tion more or less carefully. Individuals differ in this respect,
however, some studying their local habitat much more than
others. In this as well as in all other matters our observations
are in complete accord with those of Sir John Lubbock who
says: "Indeed, many of my experiences seem to show not
only a difference of character in the different species of ants,
but that even within the limits of the same species there are in-
dividual differences between ants, just as between men."*

Astata hicolor made her study in a different way from SpJiex^
ichneumonea. She first flew from the nest to a spot near by and
settled there, retmTiing, after a moment, to the nest, or else fly-
ing to another resting place. After pausing in a number of
places (in the case of the one followed in the diagram, thirteen),,
she finishes by a rapid zig-zag flight. (PI. XII., fig. 3.) An-
other wasp of this species, unicolor, differed from hicolor in not
returning to the nest from the different resting places, and in
walking from one to another of them instead of flying, although
the last part of the study was made on the wing. (PI. IX., fig.
5, and PL XII,, fig. 4.) After we had excavated a unicolor
nest, the owner dug a second hole five inches away. At
eleven o'clock of the day on which this nest was completed she
went away and was gone until fifteen minutes after one. Upon
her retiirn she was much perplexed as to the situation of her
home, there evidently being some confusion in her mind be-
tween the old nest and the new one. At first she alighted upon
the first site and scratched away a little earth, and then explored
several other places, working about for twelve minutes, when
she at last found the right spot.

Cerceris deserta was one of the wasps that objected strongly
to our presence, and she also made a great deal of fuss about
leaving her nest. ISTearly all the species circle before leaving
a spot to which they intend to return, but deserta begins her
flight with a series of short zig-zags in the form of a half circle

*Ants, Bees, and Wasps, p. 95.

218

THE SOLITARY WASPS.

on one side of the nest. (PI. IX., fig. 1.) C. nigrescetis, too, be-
•gan witli semi-circles, while C. clypeata flew entirely around
and around the opening. The contrast between the deliberate
movements of Aetata and the rapid flight of Cerceris is quite
remai'kable.

A/Mi.

The last wasp that we studied in the summer of 1897 was
Tachytes spA This species stores her nest with young grass-
hoppers and after catching them she usually has the greatest
difficulty in getting back to her nest. The above diagrams show
just the number of turns made by one individual in bringing
home her two grasshoppers.

We have now given a sufficient number of instances, from
widely separated genera, to show the care that is taken by wasps
to acquaint themselves with the surroundings of their nests. It

THE SENSE OF DIRECTION IN WASPS. 219

has also been sliown tliat in spite of all tliis care tliey frequently
have trouble in finding their way about. All these facts have
led us to conclude that wasps are guided in their movements
by their memory of localities. They go from place to place
quite readily because they are familiar with the details of th-e
landscape in the district they inhabit. Fair eyesight and a
moderately good memory on their part, are all that need be as-
sumed in this simple explanation of the problem.

When working with the social wasps some years ago we were
struck by the rapid way in which they entered and left the nest.
This, however, is only an apparent exception to the rule. We
have seen the young workers of Polistes fusca make repeated
locality studies when they first began to venture away from
home, but as they occupy the same nest all summer they of
<30urse grow more and more familiar with their surroundings,
until they become so thoroughly acquainted with them that they
can find their way without the least difficulty. We have no
doubt that with them, as with the solitary wasps, the faculty is
not instinctive, but is the direct outcome of individual experi-
ence.

220 THE SOLITARY WASPS.

CHAPTEE XYII.

THE STINGING HABIT IN WASPS.

Among writers on psycliology and biology there are few sub-
jects tbat have giA^en rise to more speculation than the origin
and purpose of the stinging habits of hymenoptera. Each
school of philosophy claims the soKtary wasp as evidence of its-
favorite opinions. That admirable observer, Fabre, remarks
that Darwin dreaded much the problem of instinct and that had
he known the results of his — Fabre's — latest observations on the-
stinging habits of solitary wasps his anxiety would have resulted
in a frank avowal of impotence to make instinct enter the mould
of his formula; while we, on the other hand, find among these
very habits good examples of the workings of natural selection.

Writers on this subject have uniformily acsumed — upon^
what evidence we have thus far been unable to discover — that
the wasp, instinctively or intelligently, uses its sting for the-
single purpose of paralyzing without killing its prey, that it
may thus provide its offspring with a fresh supply of food. To
show to what extremes this idea has been carried let us quote a
remarkable passage from Eimer. He says: "When the nest i&
ready, the wasp brings into it larvae of beetles and other insects,
which she has paralyzed by stinging them in the ganglia which
govern muscular action. This is one of the most marvellous in-
stincts that exist; since the wasp operates on various larvae with'
nervous systems of various forms, she must effect the paralysis
in various ways, and even apart from this, she makes a physio-
logical experiment which is far in advance of the knowledge of
man. The wasp thus carries one motionless but living larva
after another into her tube until it is full, and she rolls up the-

THE STINGING HABIT IN WASPS. 221

larvse and packs tiiem so skilfully that they take up as little
room as possible. Finally, she lays her egg in the store of
living food, and closes the opening with clay. Then she bo-
gins a new tube, and so lays one egg after another.

"What a wonderful contrivance! What calculation on the
part of the animal must have been necessary to discover it! The
larvae of the wasp require animal food. Dead food enclosed
in the cell would soon putrefy, living active animals would dis-
turb the egg, and accordingly the wasp paralyses grubs and
packs them like sacks of meal one after another in the cell.
How did she arrive at this habit? At the beginning she prob-
ably killed larvae by stinging them anywhere, and then placed
them in the cell. The bad results of this showed themselves;
the larvae putrefied before they could serve as food for the lar-
val wasps. In the meantime the mother-wasp discovered that
those larvae which she had stung in particular parts of the body
were motionless but still alive, and then she concluded that lar-
vae stung in this particular way could be kept for a longer
time unchanged as living motionless food. It may be suggested
that the wasp only paralyzed the larvae in order to cany them
more easily; but even if this were the case, she must, since she
now invariably acts in this way, have drawn a conclusion by de-
ductive reasoning,

"In this case it is absolutely impossible that the animal has ar-
rived at its habit otherwise than by reflection upon the facts of
experience."

Here we have as pretty an account of the habits of wasps as
could have been given in a fairy book. One can hardly be
expected to take such statements seriously, since it is certain
that the writer has no knowledge of the life histories of these
insects.

In "Mental Evolution in Animals" Mr. Eomanes says:
"Several species of the Hymenoptera display what I think may
be justly deemed the most remarkable instincts in the world.
These consist in stinging spiders, insects, and caterpillars in
their chief nerve centers, in consequence of which the victima

222 THE SOLITARY WASPS.

are not hilled outright, but rendered motionless; they are then
conveyed to s burrow previously formed by the Sphex, and,
continuing to live in their paralyzed condition for several
weeks are at last available as food for the larvse when there are
hatched. Of course the extraordinary fact which stands to be
explained is that of the precise anatomical, not to say also phy-
siological knowledge which appears to be displayed by the in-
sect in stinging only the nerve centers of its pre^."*

Before beginning any discussion of this remarkable instinct
it is most important that we have before us the facts that are to
be explained. Romanes depended upon Fabre for his knowl-
edge of the subject, and while Fabre is unquestionably the most
accurate of observers it does not necessarily follow that all of
his inferences must be accepted. We have used the quotation
from Romanes because it represents the current opinion of
naturalists on the subject, and also because it presents the in-
stinct as dependent upon several matters of fact. The first
assertion, that the prey is stung in the chief nerve-centers is not
a matter of ascertained fact at all but an inference drawn from
the observation that some of the victims are not killed but only
paralyzed. The next step in the argument is a more or less
unconscious one, namely, that the wasp does not desire to kill
but means to paralyze. Then comes the assertion that the
prey remains motionless for several weeks. So far as we know
the facts relating to this point, they are as follows: Out of our
forty-five species of solitary wasps about one-third kill their prey
outright. Of those that remain there is not a single species in
which the sting is given with invariable accuracy. To judge
from the results, they scarcely sting twice alike, since the vic-
tims of the same wasp may be killed at once or may live from
one day to six weeks, or perhaps ultimately recover. Even the
caterpiEars of Ammophila, the most distinguished surgeon
among the aculeate hymenoptera, live anywhere from two to
forty days.

To take a rapid review of some of the genera, among the
*The italics are ours.

THE STINGING HABIT IN WASPS. 223

Crabronidae the two species witli which we are familiar almost
invariably store up flies that are killed before they are brought
into the nest; our common Diodontus, as well as our StigmuSy
stores up dead aphides; Rhopalum stores dead gnats; Oxyhelus
and Bemhex kill their flies; nearly all of the beetles taken by
our Cerceris were dead, there being in all these cases an occa-
sional exception, one out of twenty-five or thirty being left alive.
Astata Mcolor kills at least half of her bugs before storing
them. Turning to the spider huntero the French Pelopaei are
always obliged, according to Fabre, to content themselves with
cadavers, while ours killed most of their spiders in stinging
them and packing them away, and so many more died shortly
after the nest was sealed that by the time the egg hatched not
more than a third were still alive. It has been supposed that
with these Pelopaei, the wasp mother protected her nurslings
from the evils of unwholesome diet by laying up large numbers
of small spiders instead of a few large ones, the process of de-
composition being hastened after a break has been made in the
skin. Agenia honibycma deliberately breaks the skin of the
one large spider which she places in her cell, by cutting off all
the legs to make it fit better. Her young are certainly fed
upon dead matter since even if the spider survived her sting it
would die under this severe operation. Our little friend, the
tornado wasp, gives her offspring but one spider, and this at
the moment of its entombment is quite as often dead as alive.
Pompilus marginatus uses the same method, killing as fre-
quently as not, and with both of the spiders that we saw taken
by Salius the sting proved fatal. As has been said Ammophila,
the most skillful operator of all, stings her caterpillars in so un-
certain and variable a manner that many of them die before
they are attacked by the larva. It must be acknowledged that
if the wasps are really aiming to produce a state of paralysis,
and especially if they are trying for even results, they are one
and all of them in the novitiate state, and are not as yet entitled
to rank as masters in the art. However this inference as to
what they are striving for is purely gratuitous since there is

224 THE SOLITARY WASPS.

nothing in such a refined operation that has the slightest utility
for them. Should the wasps themselves be permitted to ask a
question at this point they would probably inquire why we
should imagine that they need to preserve the prey for "sev-
eral weeks/' when their larvae hatch and begin to devour it in
from one to three days?

The assumption that the larvse must be nourished upon fresh
food is the central point from which all these wonderful infer-
ences are drawn. Strangely enough, in all these speculations a
very important fact has been overlooked — the fact, now fully
established, that the larvae are able to subsist on prey that has
been killed outright, and that where they are nourished upon a
single insect or spider, the food, although it must begin to de-
compose within a few days, still serves its purpose through the'
whole period of alimentation. Clearly then, the purpose of
the stinging is not to paralyze and preserve the prey alive, since
the wasp has no reason for attempting any such difficult pro-
cedure, the larva thriving quite as well upon dead as upon living
food.

Much of the mystery that surrounds the stinging operation
depends upon the supposition that the wasps are enabled by
some power that serves them in lieu of anatomical knowledge,
to sting the center of some particular ganglion without the var-
iation of a hair's breadth to the right or left.

"All," says Fabre, "from first to last shows us as clear as a
drop of water that the external structure of the victim goes for
nothing in the method used. It is the internal anatomy that
determines it. The points touched are not the most penetrable ;
they fulfill a major condition beside which penetrability is im-
important. This condition is nothing less than the immediate
neighborhood of the nervous center the influence of which must
be abolished. Body to body with its prey, soft or hard, the dep-
redator comports itself as if it knew the locality of the appara-
tus of innervation better than any one of us." "Writing of an-
other wasp (Scolia) he says that she "wishes her prey inert but
alive; she does not want a cadaver which would soon be poison to

THE STINGING HABIT IN WASPS. 225

her young. * * * ^ millimeter upward kills, a millimeter
downward paralyzes — on this slight inclination depends the race
of ScoUa."

As a striking example of the wonderful precision and discrim-
ination practiced by wasps in stinging their prey Fabre cites
Philanthiis apivoitis which, by a single stroke in the ceiwical
ganghon, inflicts death so suddenly that every muscle is relaxed.
If this manoeuvre were not performed with accuracy the wasp
would be unable to suck the honey from the dead bee; and if
the honey were left in the bee it would harm the larva for which
the victim is destined. The utility of the whole performano
rests upon the pernicious action of honey as food for young
wasps, and Fabre has done what he can to test this point by feed-
ing the larvse upon bees from wliich the honey was not removed,
as well as upon honey alone, with the result that when thus
treated they invariably died. But larvae under artificial condi-
tions die from all sorts of causes and we cannot but feel that he
has been too ready to draw his conclusions when we find that
the young of Ccrceris oniata, obseiwed by Marchal, thrive upon
bees from which the honey has not been removed.

The sting in both bees and wasps, was originally an ovipos-
itor and even today, in the egg bearers, its most important us3
is to direct and place the newly laid ovum. There can be little
doubt that its character as a weapon of offense and defense has
been added later to its primary use. In the social wasps as well
as in the social and solitary bees, its use is confined to defensive
operations, even such genera as Pollstes and Yes pa, that feed
their young on animal food, not bringing it into play to aid
them in the capture of prey, since they have sufiicient weapons
in their strong mandibles. Moreover, it is probable that there
are many solitary wasps that never sting their victims. If, in
the nest of Bemhcx, flies are found that have suiwived the
squeezing of the thorax, no one suggests that there is anything
mysterious or remarkable in the matter, but let another wasp
subdue its victim by means of the sting instead of the mandi-
bles and we overlook the explanation, so near at hand, that all
15

226 THE SOLITARY WASPS.

tbat it does, in most instances, is to overcome the resistance of
its prey. We believe that the primary pnrpose of the stinging
is to overcome resistance and to prevent the escape of the vic-
tims, and that incidentally some of them are killed and others
are paralyzed.

Monteiro saw a combat in which a wasp stabbed a spider right
in the abdomen "when it instantly curled np its legs and dropped
like dead to the ground." We, ourselves, have often witnessed
such fights and the effect of the poison of the wasp is as instan-
taneous as an electric shock. The habit of stinging in the
ganglion (where that habit is found) has doubtless been de-
veloped through natural selection, the power of quickly and ef-
fectively reducing a vigorous foe to absolute helplessness being
clearly an advantage. With those families that live on creat-
ures that are themselves armed with poisonous falces, as in the
case of spiders, we see an additional reason why the practice
of stinging to disarm them would be beneficial in the struggle
for existence; and it may be that we have here a partial olue to
the infrequent use of the sting in flycatchers.

PompUus scelestus takes a spider much larger than herself,
reducing it in a moment to a condition of absolute helplessness.
For three or four hours after it is stung it is as limp as a drop
of jelly so that it can be dragged to the nest and packed tightly
down into its close fitting tomb. Within the next twenty-four
hours it recovers, showing that the nerve-center has not been
wounded by the lance of the wasp, but only benumbed by the
transfusion of the poison. The rapid return to health has no
menace for scelestus and no advantage for the spider, since the
earth will hold it motionless until its life is ended by the grow-
ing laiwa.

But what of Sphe.r and Ammoplnlal For the first the cica-
da or grasshopper is strong and active and it is obviously desir-
able to put it into an inert condition as speedily as possible, not
only to prevent its escape, but for facility in transporting it.
AmmopJiila has often far to carry her caterpillar, and this, too,
through grass and over many a rough road. With a perfectly

THE STINGING HABIT IN WASPS, 227

limp and unresisting burden it frequently takes an hour or two,
and with a struggling captive the day would not be long enough.
To bring so soft a creature into a manageable state by using the
mandibles would reduce it to a pulpy mass and deprive it of half
its value, and the process of malaxation, which often supple-
ments the stinging, can only be practiced after the caterpillar
is quiet. As to the numerous stings that are given by Ammo-
phila it is plain, from the variations that have been found, that
the number of wounds and the order in wdiich they are given
are not important factors in her life history. From what we
have seen, one sting, or at most three, one in the middle and
another at each extremity, would be quite sufficient for all her
purposes. Perhaps the others are supernumerary, like the several
nests made by many species of birds, all but one of which are
afterward destroyed or deserted, the purpose of the stinging,
nevertheless, being to overcome, just as the purpose of nest
building is nidification. In any case the extra stings cannot be
held to invalidate the hypothesis wliich we have offered to ex-
plain the general purpose of the act.

228 THE SOLITARY WASPS.

CHAPTEK XVIII.

CONCLUSION.

Our study of the activities of wasps lias satisfied us tliat it is
impracticable to classify them in any simple way. The old no-
tion that the acts of bees, wasps, and ants were all varying forma
of instinct is no longer tenable and must give way to a more
philosophical view. It would appear to be quite certain that
there are not only instinctive acts but acts of intelligence as
well, and a third variety also — acts that ar probably due to im-
itation, although whether much or little intelligence accompan-
ies this imitation, is admittedly difficult to determine. Again,
acts that are instinctive in one species may be intelligent in an-
other, and we may even assert that there is a considerable varia-
tion in the amount of intelligence displayed by different individ-
uals of the same species. We have met with such difficulty in
our attempts to arrange the activities of wasps in different groups
that we are forced to the conclusion that any scheme of classifi-
cation is merely a convenience, useful for purposes of study or
generalization, but not to be taken for an absolutely true ex-
pression of all the facts. This kind of perplexity is well un-
derstood and allowed for in all morphological work but it has
never been fully realized in the study of habits. The expla-
nation is not far to seek. The habits of but few animals have
been studied in sufficient detail to bring out the e\T;dence that
there is as much variation on the psychological as on the mor-
phological side.

Another difficulty which has been clearly stated by both Mor-
gan and AYundt, namely, the tendency to interpret the actions
of animals in tenns of our own consciousness, must always be
with us. "VYundt himself after indirectlv criticising Romanes

CONCL USION. 229

for tills confusion, falls into it himself. He tells how, when a
boy, he made some observations upon a garden spider.

He says: "I had made myself, as a boy, a fly-trap, like a
pigeon-cote. The flies were attracted by scattered sugar, and
caught as soon as they entered the cage. Behind the trap was
a second box, separated from it by a sliding door, which could
be opened or shut at pleasure. In this I had put a large garden
spider. Cage and box were provided with glass windows on
the top, so that I could quite well observe anything that was
going on inside. At first nothing particular happened. When
some flies had been caught and the slide was drawn out the
spider, of course, rushed upon her prey and devoured them,
leaving only the legs, head, and wings. That went on for some
time. The spider was sometimes let into the cage, sometimes
confined to her own box. But one day I made a notable dis-
covery. During an absence the slide had been accidently left
©pen for some little while. When I came to shut it, I found
that there was an unusual resistance. As I looked more closely,
I saw that the spider had drawn a large number of thick
threads directly under the lifted door, and that these were pre-
venting my closing it, as though they had been so many cords
tied across it.

"What was going on in the spider's mind before she took this
step towards self-preservation — a stej), mark you, which but for
the vis major of the boy-master would have been perfectly ad-
equate to effect the desired result? The animal psychologist
will possibly say: 'The spi.der must first of all have come to
understand the mechanism of the sliding-door, and must have
said to herself that a force operating in a definite direction could
be compensated by another in the opposite direction. Then
she set to work, relying upon the perfectly correct inference
that if she could only make movement of the door impossible,
she would always have access to the victims of her murderous
desires. There you have a consideration of general issues, an
accurate prevision, and a cautious balancing of cause and effect,
end and means.' Well, I am rather inclined to explain the mat-

230 THE SOLITARY WASPS.

ter otherwise. I imagine that as the days went by there had
been formed in the mind of the spider a determinate association
on the one hand between free entry into the cage and the
pleasurable feeling attending satisfaction of the nutritive in-
stinct, and on the other between the closed slide and the un-
pleasant feeling of hunger and inhibited impulse. Now in her
free life the spider had always employed her web in the service
of the nutritive impulse. Association had therefore grown up
between definite positions of her web and definite peculiarities
of the objects to Avhich it was attached, as well as changes which
it produced in the positions of certain of these objects, — leaves,
small twigs, etc. The impression of the falling slide, that is,
called up by association the idea of other objects similarly
moved wdiich had been held in their place by threads properly
spur.; and finally there were connected with this association the
other two of pleasure and raising, unpleasantness and closing,
of the door. That was surely enough to rouse the prisoner to
action. Any other intellectual or inventive activity is entirely
unnecessary. If she had not had these associations at her dis-
posal, she would certainly never have hit upon the plan she did."
Had Wundt been familiar with the habits of spiders he would
have known that whenever they are confined they walk around
and around the cage leaving behind them lines of web. Of
course many lines passed under his little sliding door and when
he came to close it there was a slight resistance. These are the
facts. His inference that there was even the remotest inten-
tion on the part of his prisoner, to hinder the movement of the
door is entirely gratuitous. Even the simpler mental states that
are supposed to have passed through the mind of the spider were
the product of Wundt's own imagination.* He does not, liow-

*This quotation from Wundt furnishes a good example of the futility
of any attempt to understand the meaning of the actions of animals until
one has become well acquainted with their life habits. When Froude, in
his "Cat's Pilgrimage," makes the bee urge upon all animals that it is
their plain duty to make honey, while the cow expresses a pained surprise
that many insects neglect to furnish milk, we see how a wider knowledge
on their part would have prevented much misunderstanding.

CONCLUSION. 231

ever, fall into the unfortunate habit of many workers in the
field of comparative psychol'Ogy — that of withholding such a
statement of the facts as will enable one to mark them off from
the inferences of the observer.

We arrange the activities of the wasps that we have studied
into two groups, Instincts, and Acts of Intelligence, it being
understood that these classes pass by insensible stages into each
other, and that acts that are purely instinctive when performed
for the first time, are probably in some degree modified by in-
dividual experience. In this classification the question of origin
is not considered. The facts are grouped under the two heads,
the inferences that they warrant being left for later considera-
tion. Under the term Instinct we place all complex acts that
are performed previous to experience and in a similar manner
by all members of the same sex and race, leaving out as non-
essential, at tliis time, the question of whether they are or are
not accompanied by consciousness. Under Intelligence we
place those conscious actions which are more or less modifiable
by experience. It is this power that enables an insect to seek,
accept, refuse, choose, — to decline to make use of this or to turn
to account some other thing. Many writers prefer the term.
Adaptation for these activities and it possesses certain advant-
ages. With these definitions in mind, let us group the activities
of wasps under the two heads.

Instinct.

With the Fclopacus wasps" we were present on several O'oca-
sions when the young emerged from the pupa case and gnawed
their way out of the mud cell. They were limp and their wings
had not perfectly hardened, and yet when we touched them
they tried to attack us, thnisting out the sting and moving the
abdomen about in various directions. These movementsi were
well directed, and, so far as we could observe, quite as perfect
as in the adult wasp. Stinging, then, is an instinctive act.

The particular method of attack and capture practiced by
each species in securing its prey is instinctive. Amniophila

232 THE SOLITARY WASPS.

pricks a number of ganglia along tlie ventral face of tlie cater-
pillar; Pelopacus, we believe, stabs the spider in the cephalo-
thorax, and probably the several species of Pompilus do the
same. Astata hicolor adopts the same tactics in capturing her
bugs, while it is said of the fly-catchers that they commonly
overcome their victims without using the sting. It is by in-
stinct, too, that these wasps take their proper food supply, one
worms, another spiders, a third flies or beetles. So strong and
deeply seated is the preference that no fly robber ever takes
spiders, nor will the ravisher of the spiders change to beetles or
bugs.

The mode of canying their booty is a true instinct. Ponv-
pilvs takes hold of her spider anyv^here, but always drags it
over the ground, walking backward; Oxyhclus clasps her fly
•with the hind legs, while Bemhex uses the second pair to hold
hers tightly against the under side of her thorax. Each works
after her own fashion and in a way that is uniform for each
species.

The capturing of the \'ictim before the hole is made, as in
the case of P. qiiinqnen€tatns, or the reverse method pursued
by Astata, Ammophila, Bcmhcx, and others of preparing the
nest before the food supply is secured is certainly instinctive;
as is also the way in which some of these wasps act after bring-
ing the prey to the nest. For example /S'. icJnieumoiiea places
her gTasshopper just at the entrance to the excavation and then
entei's to see that all is right before dragging it in. In exper-
imenting with a French Sphcw which has the same habit, Fabre
moved the creature a little way off; the wasp came out, brought
it to the opening as before, and went within a second time.
This was repeated again and again until the patience of the nat-
uralist was exhausted, and the persistent wasp took her booty
in after her appropriate fashion. She must place the grass-
hopper just so closo to the doonvay, she must then descend and
examine the nest, and after that must come out and drag it
down. Nothing less than the performance of these acts in a
certain order satisfies her impulse. There must be no disturb-

CONCLUSION. 233

once of the regular metliod or she refuses to proceed. Again,
we see Occyheliis scratching open her nest while on the wing and
ent(!ring at once with the fly held tightly in her legs. Each
way is characteristic of the species and wonld be an important
part of any definition of the animal based upon its habits.

The general style of the nest depends upon instinct. Tri/-
poxylon uses hollow passages in trees, posts, straws, or brick
walls; Diodontiis americamts, a member of the same family,
always burrows in the ground, as do Bemheoe, Ammophila, and
Sphex. In the case of Trypoo'i/Ion the passage may be ready
for use or may require more or less preparation; the instinctive
part is the impulse that impels the insect to use a certain kind
of habitation. Any one familiar with T. rubroc'mctum would
never look for their nests in standing stems or under stones; to
use Mr. Morgan's test, he would be willing to bet on the general
style of the dwelling place. All of these acts are similarly per-
formed by individuals of the same sex and race, not in circum-
stantial detail but quite in the same way in a broad sense. Var-
iation is always present but the tendency to depart from a cer-
tain type is not excessive. In the drawing of the nest of
Cerceris nigrcscens the burrow is seen to be tortuous, this style
of work being common to many species in the genus and very
characteristic. ISTo SpJiex nor AmmopliiJa constructs any such
tunnel. The adherence of all the members of a species to a cer-
tain style of architecture, is, then, due to instinct.

The spinning of the cocoon, in those species in which the larva
is protected in this manner, and its shape, are instinctive. "We
find that closely allied species in the same genus make very dif-
ferent cocoons as is seen in T. ruhrocinctum and T. hidentatum.
Some wasps never cover themselves with a cocoon, as in the Au-
stralian species Alastor eriiirgiis and Ahispa splendida* It
is a well known fact that silk w^orms sometimes omit the spin-
ning of a cocoon; but this does not affect the argimient since

*Nests and Habits of Australian Vespidae and Larridae, by Walter
"W. Froggatt, Proceedings Linnean Society of N. S. W., Vol. IX.,
Series 2nd.

234 THE SOLITARY WASPS.

the descendants of these individuals make the characteristic cov-
ering. Such cases are probably due to individual variation or
perhaps to atavism, this throwing back being not imoommon
among forms that are well known.

iN^ot all of the instinctive facts here enumerated are displayed
by each species studied, although as a general proposition they
are common to most of them. We have doubtless overlooked
some activities that should come under this head as we have
not made a thorough study of any sufficient number of species
to make a final settlement of the matter. For convenience we
give the eight primary instincts that we have enumerated in
tabular form.

Instincts.

1. Stinging.

2. Taking a particular kind of food.

3. Method of attacking and capturing prey.

4. Method of caiTjang prey.

5. Preparing nest and then capturing prey, or the reverse.

6. The mode of taking prey into the nest,
v. The general style or locality of nest.

8. The spinning or not spinning of a cocoon, and its spe-
cific fonn when one is made.

Intelligence.

It is obviously more difficult to distinguish actions of this
class than of the other. One must be familiar with the normal
conditions of the insects in question before he is able to note
those slight changes in the en\'ironment that offer some oppor-
tunity for an adaptation of means to ends, or before he is com-
petent to devise experiments which will test their powers in this
direction.

We find two classes of intelligent actions among the hymen-
optera which are sufficiently distinct to be considered separately,
although, like all natural groups, they grade into each other.
The first of these includes those actions that are performed bj

CONCL USION. 235

large niimbers in a similar fashion nnder like conditions, wliile
in the second class each act is an individual affair, as where a
single Avasp, uninfluenced in any way by the example of those
about it, displays unusual intelligence in grappling with the
affairs of life. Examples of the first class are found in sucli
modifications of instinct as are shown by Pelopacus and other
wasps in the character of their habitations. Pelopacus, instead
of building in hollow trees or under shelving rocks, as was the
ancient custom of the race, now nests in chimneys, or under
the eaves of buildings. "We have found T. ruhrociiwtum tak-
ing advantage of the face of a straw stack that had been cut off
smoothly as the cattle were fed through the winter. The same
power of adaptation is shown by Fal^re's experiment with Osmia,
in which he took two dozen nests in shells from a quarry, Avhere
the bees had been nesting for centuries, and placed them
in his study along with some empty shells and some hollow
stems. When the bees come out, in the spring, nearly all of
them selected the stalks to build in as being better suited to
their use than the shells. All of these changes are intelligent
adaptations to new modes of life, serving to keep the species in
harmony with its surroundings. The same thing may be seen
when a number of social Avasps work together to replace the roof
of their nest when it has been torn off.

An instance of the second class is seen in one of our examples
of Pompilus marginatum. This species, while searching for a
nesting-place, leaves its spider lying on the ground or hides it
under a lump of earth, in either of which positions the booty
is subject to the attacks of ants; the wasp in question improved
upon the custom of her tribe by carrying the spider up into a
plant and hanging it there. We have now and then seen a
queen of PoUstes fiisca occupy a comb of the previous year in-
stead of building a new one for herself, showing a better mental
equipment than her sistere who were not strong minded enough
to change their M^ays and so built new nests alongside of un-
occupied old ones which Avere in good condition. In Bembeac
society it is good form to close the door on leavins; home, but

236 THE SOLITARY WASPS.

Bometimes a wasp will save time by leaving tlie entrance open.
This, however, is a doubtful case rs the advantage would, per-
haps, be more than balanced by the exposure of the nest to par-
asites. The most conspicuous example that we have seen of
intelligence among wasps, was in that individual of Ammophila
that rose above her fellows by using a stone to pound down, the
earth over her nest.

The general impression that remains wdth us as a result of our
study of these activities is that their complexity and perfection
have been greatly overestimated. "We have found them in all
stages of development and are convinced that they have passed
through many degrees, from the simple to the complex, by the
action of natural selection. Indeed, we find in them beautiful
examples of the survival of the fittest.

INDEX.

Agenia architecta, date of appearance of, 165; short larval life of, 166.

BOMBYCiNA, observation on ruutilation of spider by, 164; Dimmock's

account of habits of, 165.

Ammophila, variations among species of, in method of closing nest, 20;
Fabre's conclusions from the study of, contrasted with ours, 30, 31 .

GRACILIS, great distance over which prey is carried by, 25-27; desertion

of caterpillar by, 26; condition of caterpillar stung by, 26; failure of
instinct in, 27.

HiRSUTA, method of stinging of, 12; success of experiments with, 12.

SABULOSA, failure of experiments with, 12.

URNARiA, feeds on nectar of flowers, 6; sense of locality in, 7, 8; locality

study of, 212, 213; her mode of carrying caterpillar, 7, 30; prey of, 7
her preference for clear warm weather, 8; individual variation in, 9
hunting habits of, 9; her mode of attack, 10; malaxation by, 11, 12
stinging habits of, 11, 12; failure in experimenting with, 12; variation
in the thoroughness of her stinging, 13; condition of caterpillars stung
by, 13-18; length of time that caterpillars survive the sting of, 13;
length of egg and larval stages in, 18; locality and character of her
nest, 18; position of her egg on larva, 18; her method of digging, 19;
her method of making a temporary closure of nest, 19; time elapsing
between storing of her caterpillars, 21; final closure of her nest, 21;
her habit of frequently revisiting nest, 21; variation in her manner of
closing nest, 21, 22; using pebble as a tool, 23; her peculiar conduct
resulting in loss of egg, 27; number of caterpillars stored by, 28.

YARROWi, Williston's notes on habits of, 23-25.

Aporus fasciatus, goes backward when carrying prey, 55; depends upon
land-marks for recognizing locality, 55; her method of digging, 56;
position of her egg on spider, 56; length of egg stage in, 56; does not
sting severely, 56; probably depends upon close packing to keep spider
quiet, 56; contrast between two individuals of, 57; length of time occu-
pied by, in digging nest, 56, 57; character of nest of, 57; takes Atti-
dae, 57; her habit of filling up partly made nests, 57; date of appear-
ance of, 57.
Arachnida, concentration of nervous system in, 81.

238 INDEX.

AsHMEAD, W. H,, on habits of Stlgmus ai'genUfrons, 45; on prey of Trij-
poxylon albopilosum, 86.

AsTATA BicoLOR, date of appearance of, 92; her deliberative character, 93;
her prey, 93; length of time it takes her to catch a bug, 93; her method
of digging, 94; her habit of sleeping in nest, 94, 95; situation and ap-
pearance of nest of, 95; her habit of leaving nest open during absence,
95; malaxation by, 95; condition of bugs found in nest of, 95, 96; her
freedom from parasites, 95; her method of stinging, 96; her habit of
enlarging nest from day to day, 96; locality study of, 217.

Leuthstromii, observation on, 98.

UNTCOLOR, variation in size of, 88; locality study of, 88, 217; prey of,

88; her method of carrying prey and of digging nest, 88, 89; her spells
of work alternating with those of rest, 89; her habit of leaving nest
open when absent, 89; character of her nest, 90; position of her egg on
bug, 90: length of egg and larval stages in, 91; attacked by parasites,
91; her timidity while storing nest, 91, 92; condition of bugs found in
nests of, 92.

Balanius nasicus, preyed upon by Cerceris clyj^eafa, 111.

Bartram, on habits of Sphex, 72.

Bates, H. W., on locality study of Monedula aigvata, 35; on habits of
same species, 70; on habits of Beinbrx ciliaia, 70.

Belt, Thomas, on locality study of PoUstes carnifex, 35; on ants pro-
tecting frog-hoppers from wasps, 100.

Bembex ciliata, circles when leaving nest, 70; leaves nest open, 70.

rostrata, account of habits of, by Wesenberg, 70, 71.

spinolae, size of colony of, 58; has less numerous progeny than other

wasps, 59; her habit of feeding young from day to day, 59; her diffi-
culty in deciding where to dig, 59; method of digging of, 59; time oc-
cupied in digging nest and clearing away debris by, 60; uselessness of
hiding entrance to nest of, 60; length of time occupied in catching fly
by, 60; her method of taking fly into nest, 60; character of nest of,
61; sense of locality of, 61; departing from nests and returning to them
in company, 62; quarrelsome habits of, 62, 63; thievish propensities
of, 63; works from four to five hours a day, 63; does not work in
cloudy weather, 63; her tolerance of parasitic flies, 64; number of
parasitic larvae found in nests of, 64; position of her egg on fly, 66;
length of egg stage, 66; condition of flies stored by, 66, 67; observa-
tion on stinging habit oif, 67; suggestion as to origin of habits of, 67,
68; differs from Monedula punctata, 70; experiments to determine
the number of nests visited by female of, at one time, 71.

Bonnet, quoted by Westwood on habits of Pelopaeus, 72.

Brehm, on mutilation of spiders by Agenia punctata., 164.

INDEX. 239

Cebatina dupla, order in which eggs of, hatch, 86; her habit of watch-
ing over young, 87.
Cekceris clypeata, date of appearance of, 109; wariness of, 110; prey
of. 111; her method of carrying prey. 111; her habit of standing in en-
trance of nest, 112; her locality study, 113; her method of work, 113;
leaves nest open during absence but closes it when within, 113; exper-
iments on stinging habits of, 114; condition of beetles in nest of, 114.

DESERTA, wariness of, 115; method of carrying prey of, 115; condition

of prey after being stung by, 116; locality study of, 116, 217, 218.

NiGRESCENS, wariness of, 116; prey of, 117; condition of prey after

being stung by, 117.

OBNATA, killing Halictus, 105; nest of, 200; pray of, 200; position of

egg of, on bee, 200; experiments on, 200; her method of stinging in
captivity, 201; malaxation by, 201; paralysis of bee due to diffusion of
poison of, and not to a wound of ganglion, 202; brutual methods of,
202; licks juice of bee as it exudes, 203; purpose of, in paralyzing bee,
203; condition of victims after having been stung by, 204; her bees
die from day to day if stung without malaxation, 206; rapid drying up
of bees that are stung by, 207; resume of observations on fifteen nests
of, 208; not a master in the art of paralyzmg, 209; errors of instinct
of, 209, 210.

Ceropales frateena, toWowmg Po7npilus scelestus,l^i, 155.

Chironomus, species of, found in nests of Hhopalum, 43.

Chlorion coeruleum, date of appearance of, 173; nest of, 174; prey of,
174; condition of prey stung by, 174; position of egg of, on cricket,
174; length of egg and larval stages, 174.

Cheysididae, order in which eggs of, hatch, 87; young of, gnawing a hole
through stem, 87.

Crabro stirpicola, date of first appearance of, 46; locality of nest of, 46;
contrasted with other wasps as to manner, 46; her method of removing
pith, 47; works continuously night and day to finish nest, 49; time
taken by, in capturing flies, 50; industry of, 50; length of tunnel of,
51; contents of cell of, 51; numbfer of flies stored by, 51; species used
by, 51; length of larval life of, 52; condition of flies in cells of, 52;
length of pupal stage of, 52; larva of, does not require fresh food, 52.

Cdrtis, quoted by West wood on habits of Mellinus, 72.

Dakwin, Charles, on evolution of stinging habit in wasps that paralyze
their prey, 31, 32.

DiMMocK, George, on habits of Agenia hombycina, 165.

DioDONTUs AMERiCANus, date of appearance of, 99; preying on aphides,
99; relations of, with ants, 99; malaxation of aphides by, 101; does not
sting aphides, 102; location of nest of, 103; method of digging of, 103;

240 INDEX.

number of aphides found in nest of, 103; date of disappearance of, 104;
males of, 104; parasites of, lOi; sucking juices from aphides, 105: con-
dition of aphides in nest of, 105; duration of egg and larval stages, 106.

CORNIGER, preying on aphides, 107.

GRACILIS, preying on aphides, 107.

Dunning, S. W., on finding flies alive in nest of Bembex, 66; notes of, on

Pelopaeus cementarius, 188.
EiMEB, on stinging habits in wasps, 220-222.
EvERSMANN, on finding spiders alive in nests of Pelopaeus distillarius,

187.
Fabre, J. H., on stinging habits of Ammophila hirsuta under artificial
conditions, 12; on habit of closing nest as soon as made, in A, argen-
tata and A. sabulosa, 20; on unsusal habit of catching prey first
and then digging nest, in A. hirsuta, 20; on automatically perfect in-
stincts of ^«i?7J0p/)/^a, 30,31; on French species of Sphex, 38-40; on
relation between Bembex and parasites, 65; on method of parasite
in depositing egg on prey of Beinbex, 65; on number of flies consumed
by larva of Bembex, 66; on Oxybelus carrying fly impaled on sting,
73; on habits of Philanthus apivorus, 105; on habits of Pompilus,
125; on comparative value of his observations on solitary wasps, 181;
on method of capture of prey by Pelopaeus, 190; on spiders of Pelo-
paeus being nearly always killed, 191; on his belief that Darwin would
have admitted that the habits of the solitary wasps could not be ex-
plained by the theory of natural selection, 220; on importance of para-
lyzing instead of killing prey, 224; on importance of internal anatomy
rather than of external structure in determining method used by wasp
in stinging prey, 224.

GossE, P. H., on intelligence of Pelopaeus flavipes, 197, 198.

GouREAU, on mutilation of spiders by wasps, 164.

Habit of. several species of feeding young from day to day, 71, 72.

Halictus disparalis, preyed upon by Philanthus punctatus, 119, 120.

Harpactopus ABDOMiNALis, date of appearance of, 174; prey of, 175;
method of carrying locust of, 175; position of egg of, on locust, 175;
condition of locust stung by, 175.

Hudson, W. H., on habits of Monedula punctata, 69.

Instinct, defined, 231.

Instincts of solitary wasps, classification of, 234.

Intelligence of solitary wasps, 231, 234-236.

Locality sense in wasps, 211-219; Darwin's theory of dead-reckoning in
relation to, 211; Lubbock and Romanes quoted against this explana-
tion of, 211; confused by changes in surroundings, 215, 216.

Lubbock, Sir John, on individuality in ants, 217.

INDEX. 241

Lyroda subita, date of appearance of, 369; prey of, 169; feeding of young
from day to day by, 170; condition of prey after being stung by, 170;
number of crickets eaten by larva of, 171.

Maindron, on variability of nests of Felopaeiis, 179,

Marchal, Paul, on Cerceris ornata, 200-210.

Melittobia, parasitic on Trypoxylon^ 86.

Monedula punctata, feeds larva from day to day, 69; captures no prey
until egg hatches, 69; uses fire-flies and other insects as well as flies, 69.

signata. Bates' observation on locality study of, 35; preys upon only

one species, 70.

MoNTEiRO, on finding spiders alive in nests of Pelopaeus spirlfex, 186,
187; on combat between wasp and spider, 187.

Mutilation of spiders by wasps, 164.

Nests, see under various species.

Omalus corruscans, parasitic upon Diodontus americanus, 104.

OxYBELUs QUADRiNOTATUS, her method of carrying fly, 73; of storing nest,
74; closes nest when going away but leaves it open while she is within,
74; makes nest before first fly is captured, 74; position of her egg on
fly, 74; condition of flies in nest of, 74; character of nest of, 74; length
of egg stage in, 75; according to Verhoeff, cannot sting, but crushes
thorax of fly, 75; date of appearance of, 75.

Pachyopthalmus aurifrons, parasitic on Tryjyoxylon, 86.

Packard, on the nesting habits of SpJiex icJmenrnonea, 39.

Pelopaeus, number of generations of, in one year, 176; locality of nests in
American species of, 177; in French species of, 177; method of nest-
building in, 177; variation in nest-building habits of, 177; variability
of nests of, in Indian archipelago, 179; prey of, 179; number of spiders
packed into one cell by, 180; notes showing contents of nests of, 180;
method of capturingand stinging prey ofj 181; observation upon sting-
ing habits of, 182; two or three spiders dislodged before one is captured
by, 183; condition of spiders found in nests of, 185; table showing con-
dition of spiders in nests of, 186; French species of, kill their prey, 186,
egg of, laid on last spider brought in, 187: time required to fill cell of,
187; effect of poison of, as noted by Monteiro and Eversmann, 187;
variation of different species of, 187; eating habits of larva of, 188,
189; length of larval stage of, 189; variation in number of spiders con-
sumed by larva of, 189; difference between French and American
species of, 192; conclusions to be drawn from study of, 193; cocoon of,
193; method of emerging from cocoon of, 193; stinging habit congeni-
tal and instinctive in, 193; table showing that spiders in nests of, die
from day to day, 196; summary of habits of, 198, 199.

242 INDEX.

Pelopaeus cementaRius, found in Wisconsin, 176; Mr. Dunning'a notes
showing condition of spiders found in nest of, 188; length of egg stage
in, 188; effect of venom of, on cray-fish, 191; on spiders, 191, 195.

COEBULEUS, most common species in Wisconsin, 176.

DiSTiLLARius, spiders found alive in nests of, by Eversmann, 187.

FLAViPES, intelligence of, as noted by Gosse, 197, 198.

SPIRIFEX, observations on, by Monteiro, 186.

Philanthus punctatus, date of appearance of, 117; several individuals
of, hatching out and living in same nest, 118; habits of colony of, 118;
method of digging of, 118, 119; prey of, 119; number of bees stored in
an afternoon by, 120; experiments on stinging habits of, 122; condi-
tion of bees after being stung by, 122; character of nest of, 123; nesting
habits of males of, 123, 12i.
PoLisTES CARNiFEx, locality study of, noted by Belt, 35.
fusca, sometimes uses old nests, 177, 235; effect of venom of, on cray-
fish, 193; locality study made by young workers of, before leaving
nest, 219; takes prey without stinging, 102, 225.
PoMPiLiDAE, prey of, 125; variation in habits among species of, 125; nest-
ing habits of French species of, 125.
PoMPiLUS BiGUTTATUS, date of appearance of, 138; resembles quinquenota-
tus in habits, 138; starts several nests, 139; nest of, 139; method of carry-
ing prey of, 139; position of <^gg of, on spider, 110; length of egg, larval,
and pupal stages of, 110; condition of spiders after being stung by, 110.
CALIPTERUS, date of appearance of, 114; nest of, 114; prey of, 144; con-
dition of spiders stung by, 141; position of egg of, on spider, 144;
length of Qgg stage, 144.
FUSCiPENNis, prey of, 140; biting legs of spider, 140, 141, 143; dig-
ging habits of, 141; mode of carrying prey of, 141; method of closing
nest of, 141, 142; afraid of ants, 142; sense of locality in, 142, 214;
position of egg of, on spider, 142; length of egg stage in, 143; condi-
tion of spiders after being stung by, 143; species of spiders taken by,
143; number of legs cut from spiders by, 144; locality study of, 213.

iNTERRUPTUS, date of appearance of, 152; digging habits of, 152;

prey of, 152; temporary disposition of prey by, 152; digs more than
one nest, 153; method of closing nest of, 153; condition of spider stung
by, 153; position of egg of, on spider, 153.
MARGiNATUS, date of appearance of, 144; excitability of, 145; condi-
tion of spiders stung by, 145, 147, 149; method of carrying prey of,
146; her long hunt for a suitable nesting place, 148; temporary dispo-
sition of prey by, 148; description of capture of Lrcosid by, 149; digs
her nest after capturing prey, 151.

INDEX. 243

PoMPiLus QuiNQUENoTATus, date of appearance of, 126; method of digejing
of, 12G; prey of, 126; method of carrying prey of, 127, 129; method of
closing and concealing nest of, 127; nest of, difficult to excavate, 127,
128; nest of, invaded by small ants, 128; confines herself to one species
of spider, 129; often hangs spider on plant while nest is being made,
129; is capricious in selecting spot for nest, 130; failure of experiments
to determine stinging method of, 131, 132; robs her neighbors, 133;
variation in nests of, 131, 135; length of egg and larval stages in, 136;
notes showing effect of sting of, upon spider, 136, 137; inexactness of
stinging methods in, 138; sometimes loses her way, 135, 213,

SCELESTUS, date of appearance of, 153; prey of, 153; bites legs of spi-
der, 154, 158; flattens herself and crawls around nest, 157; sleeping
habits of, 158; temporary disposition of prey by, 159; mode of filling
nest of, 159; position of egg of, on spider, 160; pursuit of, by parasites,
154, 155; makes long pauses while transporting spider, 155; diagram
showing road over which spider was carried by, 156; condition of spi-
der immediately after having been stung by, 160; recovery of spider
from sting of, 161; experiment with stink-bug upon spider taken by,
161; experiment of wounding ganglion of spider taken by, 162; prey
of, buried alive, 163.

Pbiononyx ateata, date of appearance of , 171; prey of, 171; flattens herself
on ground and crawls about, 171; method of carrying locust of, 172;
condition of locust stung by, 172; position of egg of, on locust, 172.

Rhopalum pedicellatum, nests in stumps, 42; is a long time in finding
prey, 42; has strong power of localization, 43; description of nest of,
43; number and condition of gnats found in nests of, 43; length of egg
stage in, 43.

RUBROCINCTUM nests in stalks, 43; number of cells stored by, 43; prey

of, 43; number of gnats found in each cell of, 43; gnats found in nests
of, all dead, 44.

Romanes, G. J., on stinging habits of hymenoptera, 221.

Salius conicus, date of appearance of, 53; method of capturing and sting-
ing a Lycosid of, 53, 54; spider killed by sting of, 54; experiments
with, 54; moves backward when carrying prey, 55.

Social wasps, summary of general habits of, 3.

Solitary wasps, general habits of, 4.

Sphex, habits of, noted by Fabre, 39, 40.

iCHNEUMONEA, date of appearance of, 33; nests begun and deserted

by, 33; nest of, 33; method of digging of, 33; appearance of nest of,
34; studies locality of nest before leaving it, 34, 214, 215; reas ing
power of, .34; her method of carrying prey and of taking it into nest,

244 INDEX.

37; position of egg of, on prey, 37; position of grasshopper in nest, 37;
condition of prey after being stung by, 38; length of time occupied in
making nest by, 39.

Stigmus americanus, nests in stumps, 44; collects aphides, 44; collecting
journeys of, occupy three or four minutes, 44; several individuals of,
use the same gallery, 44; description of nest of, 44; position of egg of,
on aphis, 44; number and condition of aphides found in nests of, 44;
parasites of, 45.

ARGENTiFRONS, provisions nest with aphides, 45.

TROGLODYTES, nests in straws and preys upon larva of a Thrips, 45.

Stinging habit in solitary wasps, variation of, in different species, 222;
species that use it to kill, 223; purpose of, 226, 227; origin of, 225.

Stink-bug, refused by spider, 161.

Tachytes sp?, date of appearance of, 167; remarkable method of progres-
sion when carrying prey, 167; prey of, 167; variation in number of
grasshoppers stored by, 168; position of egg of, on grasshopper, 168;
length of egg and larval stages in, 168; condition of grasshoppers stung
by, 168; perfection of method of paralyzing prey in, 168; has difficulty
in finding way back to nest after capturing grasshopper, 218.

Trypoxylon, immense numbers of spiders destroyed by, 87.

ALBOPILOSUM, takes larger spiders than r?<&rocfneoW?», 85; preparation

of nest by, 85; condition of spiders in nest of, 85; parasites of, 8o.

bidhntatum, habits of, 83; stinging habits of, 83; order in which per-
fect insects emerged from cocoons of, in one set of cells, 80; cocoon of,
differs from those of ruhrocinctum and alhopUosum, 86.

rubrocinctum, using holes already excavated, 77; preparation of nests

of, 78; length of time occupied in storing nest by, 78; cooperation of
males and females of, 79; protection of nest by male of, 79; method of
taking in spider of, 80; male of, sometimes assists in storing nest, 80;
the packing in of the spider by, 80; number of spiders used by, de-
pendent upon their size, 80; accuracy shown by, in never selecting a
spider too large for calibre of straw, 81; refuses to sting in captivity,
81; position of egg of, on spider, 81; condition of spiders found in nests
of, 82; table showing length of life of spiders that have been stung by,
83; length of egg and larval stages in, 83; eating habits of larva
of, 84; locality sense of, 84; length of cocoon stage, 84; order in which
perfect insects emerged" from cocoons of, in one set of cells, 86.

Venom of wasps, experiments with Polistes fusca on grasshopper, 38; ex-
periments on cray-fish, spiders and caterpillars with Pelopaeua ce-
mentariua, Polistes fusca and Vespa maculata, 193-195.

Vespa MACULATA, experiment on venom of, with caterpillar, 195

INDEX. 245

Wesenberg, on habits of Bernhex rostrata, 70, 71.

Westwood, on Ammophila^s method of carrying caterpillar, 30; on habits

of Stigmns troglodytes, 45; on Mellinus feeding her young from day

to day, 72.
WiLLiSTON, S. W., on habits of Amynophila Yarroivl, 22-25.
WuNDT, on experiment with garden spider, 229; erroneous inferences of,

due to lack of familiarity with habits of spiders, 230.

WISCONSIN GEOL. AND NAT. HIST. SURVEY.

BULLETIN NO. II, PL. VIII,

1 -•-■>l^|)lllJ^^l';''/;,^i'.'•''^■'',,,.l)to,

i|^^,.^^^^^^

PLATE VIII.

FiG3. 1-2. Nests of Ammophila ui'naria, % natural size.

Figs. 3-4. Nests of Ammophila urnaria, natural size.

Fig. 5. Caterpillar with egg of Ammophila urnaria.

Fig. 6. Nest of Cerceris nigrescens, tunnel 33^ inches long.

Fig. 7. Nest of Oxgbelus quadrinofafus, natural size.

Fig. 8. Side view of spider: A, nervous system. (After Emerton.)

WISCONSIN GEOL. AND NAT. HIST. SURVEY.

BULLETIN NO. II. PL. IX.

PLATE IX.

Fig. 1. Locality study of Cerceris deserta.

Fig. 2. Lycosa Kochil, found in nest of Agenia homhycina., X 2.

Fig. 3. Nest of Agenia homhycina, X 2.

Fig. 4. Nest of Bemhex spinolae; tunnel 33^ inches long; pocket 2 in-
ches below surface.

Fig. 5. Locality study of Astata unicolor. The continuous line shows
the course walked over by the wasp; the short marks at a right
angle indicate resting-places; the broken line indicates flight.

Fig. 6. Nest of Astata hicolor ; tunnel 23^1 inches long; pocket 1^^ in-
ches below surface.

WISCONSIN GEOL. AND NAT. HIST. SURVEY.

BULLETIN NO. II, PL. X.

^i^rSSf^

PLATE X.

Pig, 1. Variety of nest of Pelopaeus coerulcus, showing lumps of mud
plastered on outside.

Fig. 2. Vertical cell of nest of Pclojiaeus coeA'uleus.

Fig. 3. Horizontal cells of nest of Pelopaens coeruleus.

Fig. 4. Nervous system of Ilali/ctus. (After Marchal.)

Fig. 5. Nest of Dlodontus ameriGanus, natural size.

Fig. 6. Nest of Pompilus qulnqueaofafus, nearly natural size.

Figs. 7-8. Examples of Epeira strix that have been paralyzed and
hung up on bean and sorrel plants by Pom^yilus quinque-
notafus, that they may be out of the way of ants while
she digs her nest.

WISCONSIN GEOL. AND NAT. HIST. SURVEY.

BULLETIN NO. II, PL. XI.

^^^'M^'^^Mf

PLATE XI.

Fig. 1. Nest of Sphex ichneumonea ; tunnel 73^ inches long; pocket J^
inch by % inch.

Fig. 2. Nest of PMlanthus punctatus ; A — B, 33^^ inches; B — C, 5 inches;
C— D, 14 inches; D— E, 8 inches.

Fig. 3. Nest of Astata unicolor; A— B, 2 inches; B — C, IJ^ inches;
A — C, 2 inches; C, four cells where the bugs were stored. B — C
gallery occupied by wasp while in nest.

Fig. 4. Nest of Chlorion coeruleum; nearly % natural size.

Fig. 5. Nest of Tachytes sp?,; tunnel 2 inches long; pocket 13^ inches
below surface.

Fig. 6. Nest of Crabro stlrpicola in blackberry stem; X 2.

Fig. 7. Bottle fastened to stem to measure work of Crabro stirpicola.

WISCONSIN GEOL. AND NAT. HIST. SURVEY

BULLETIN NO. II, PL. XII.

PLATE XII.

Fig. 1. A thorough locality study by Sphex ich/ieumonea.

Fig. 2. A hasty locality study by Sphex Ichneumonea.

Fig. 3. Locality study of Astata blcolor. The wasp flew from nest to 1,
paused a moment, then flew back; then to 2, paused and flew
back; then to 3, paused, then to 4, paused and flew back to nest;
flew to 4, 5, 6, 7, 8 and 9, pausing at each spot, and flew back to
nest along 10; flew, successively, along 11, 12 and 13, resting at
the spots designated; from 13 she circled around nest in direc-
tion of arrow points and departed.

Fig. 4. A second locality study of Astata unicolor. The continuous line
shows the course walked over by the wasp, the short marks at
right angles representing resting places; the broken line indi-
cates flight. Line 1 shows the first study, leading back to the
nest, and line 2 the second, ending in flight and departure.

Fig. 5. Course followed by Pompilus fuseipennis in finding her spider
and in retracing her steps to the nest. The nest being com-
pleted the wasp went skimming over the ground as indicated by
the line, until the spider, which had previously been stung and
placed upon a leaf, was found. She then dragged it some dis-
tance beyond the nest to the point 2, from which place she took
it to the nest.
The locality studies are all very much reduced.

WISCONSIN GEOL. AND NAT. HIST. SURVEY.

BULLETIN II PL. XIII

J. H. Emerron del

HOfilHWESTIfW L!IHO 0)

PLATE XIII.

Fig. 1. Agenia architeeia p , X 4.

Fig. 2. Salius conicus ? , X 4.

Fig. 3. Oxyheliis quadrinofafus ? , X 4:.

Fig. 4. Tachytes npf ^ ,y^L

Fig. 5. Aporus fasciatua ? , X i'

WISCONSIN GEOL, AND NAT. HIST. SURVEY.

BU LLETIN II PL. XIV

J. H. Emerton del.

NoRTMwsrwn iitho c

PLATE XIV.

Fig. 1. Trypoxylon ruhrooinctum 2 ,Y^i.

Fig. 2. Stigmus americanus ? , X 4.

Fig. 3. Diodontus americanus ? , X 4:.

Fig. 4. Priononyx atrata ? , X 2.

SMITHSONIAN INSTITUTION LIBRARIES

DDBMtEEt M

3 ^Qflfl

nhent QL569.P4X
On the instincts and habits of the solit