Guide to the study of insects, and a treatise on those injurious and beneficial to crops: for the use of colleges, farm-schools, and agriculturists online

tiers." When about to transform the larvae spin a thin cover-
ing, thus closing over the cell.

In Polistes the paraglossre are slender, and a little longer
than the long, or as in one instance noticed by us in P. Cana-
densis, barrel-shaped ligula, which is split at the end ; the palpi
are stouter, while the whole body is much longer than in Vespa ;
the abdomen is subpedunculate, and the thorax is rather ob-
long than spherical, as in Vespa.

The larva differs from that of Vespa in its much larger head,
and shorter, more ovoid form of the body, which is dilated in
front so as to retain the insect in its cell, while the tip is
more acute ; the antennal tubercles are closer together ; the
rlypeus is more regularly triangular and more distinct, while
the labrum is much larger and excessively swollen, as are the
mouth-parts generally. The mandibles are bidentate, where in
Vespa they are tridentate. The pupa differs from that of Vespa,
besides the usual generic characters, in having the tubercle on
the head smaller.

The nests of Polistes (Plate 5, Fig. 4, nest of P. annularis
Fabr., from Saussure) are not covered in by a papery wall as in
Yespa, but may be found attached to bushes, with the mouth
of the cells pointed downwards. While at Burksville Junction,
Va., in the last week of April, I had an opportunity of watch-
ing three species beginning their cells on the same clump of
bushes. They all worked in the same method, and the cells
only differed slightly in size. The cells were formed mostly of



152 HYMENOPTERA.

crude silk, and the threads could be seen crossing each other, the
same structure being observed at the top and bottom of each
cell.

In the three-celled nest of Polistes (Plate 5, Fig. 5, 5 a)
first noticed April 29th, there were but two eggs deposited, the
third cell being without an egg, and a little smaller, and
the rim not so high as in the other two. The outer edge did
not seem to be perfectly circular, though stated by Water-
house to be so in the incipient cells, for in some cases we de-
tected two slight angles, thus making three sides, which,
however, would be easily overlooked on casual observation ;
as there are only two sideg within, the cell, from being at its
earliest inception hemispherical, or "saucer-shaped," becomes
five, and subsequently six-sided, and thus from being cir-
cular, it is converted by the wasps into a hexagonal cell. In
some cells, perhaps a majority, both in this and the other spe-
cies, the newly made rim of the small cells is thinner than the
parts below, and slightly bent inwards ; thus being quite the re-
verse of the thickened rim of the cells of the Hive Bee. It
would seem that the wasp plasters on more silk, especially on
the angles, building them out, and making them more promi-
nent, in order to complete, when other cells are added, their
hexagonal form. The three cells are of much the same size
and height when the third egg is laid, as we observed in another
nest, that of Polistes Canadensis (Linn.), built at the Defences
of Washington, near Munson's Hill, June 9th.

Again, when one or two more cells have been added to the
nest, and there are four or five in all (Plate 5, Fig. 6 ; 6 a, top
view, in which there are four cells), two of them are nearly
twice as large as the others, while the fifth has been just begun,
and is eggless. The form of the two which run up much higher
than the others is the same as that of the smaller and shorter
ones, i.e. they are on one side nearly semicircular, and on the
other, partly hexagonal, and the angular sides show a tendency
to be even more circular than when the others are built around
them, for the little architect seems to bring out the angles
more prominently when carrying up the walls of the other cells.
Thus she builds, as if by design, one and the same cell both
by the "circular" and "hexagonal" methods, afterwards adopt-



VESPARI^E. 153

ing only the latter, and if she devotes her attentions specially
to plastering the corners alone, with the design of making the
cell six-sided, then we must allow, contrary to Mr. Water-
house's views, that the wasp builds the hexagon by choice, and
not as the mere result of her blindly "working in segments of
circles ;" for if our point be proved, mid the most careful obser-
vation of the wasp while at work is needed to prove it, then it
may be shown that the wasp is a free agent, and can abandon
one method of working at a certain stage of her work, and
adopt a different mode of operating.

The eggs are oval, pointed at the end, and glued to the in-
side of the cell. They are situated midway from the top and
bottom of the incipient cell, and placed on the innermost sides,
so that in a group of several cells the eggs are close together,
only separated by the thin cellular walls. In a completed cell
the egg is placed very near the bottom.

For several days a Polistes Canadensis was engaged in build-
ing its nest in my tent in camp near Washington. When first
noticed on June 9th, there were three cells, two of which con-
tained eggs; and it was not for two days, the llth, that the
third cell was completed, and a third egg deposited in it. The
wasp paid especial attention to strengthening the pedicel, going
over it repeatedly for an hour or two with its tongue, as if lay-
ing on more silken matter, and then proved the work by its
swiftly vibrating antennae. It would often fly out of the tent,
and on its return anxiously examine each cell, thrusting its head
deep down into each one. It gradually became accustomed to
my presence, but eventually abandoned the nest, without adding
more cells. The others, while at work on the bushes, abscond-
ed at my approach, and seemed very wary and distrustful, as
if desirous of concealing their abodes. Mr. Smith has found
Trig malys bipustulatus to be a parasite on Polistes lanio Fabr.
(P. Canadensis Linn.), from St. Salvador, S. A.

Saussure arranges the higher Vespidse into two parallel series.
Vespa is offset by Chartergus and Nectarina ; lower down we
find Tatua and Synceca, while Polistes is offset by Polybia.
These five genera are tropical, and in their habits, the general
appearance of their nests, and in the number of individuals
represent Vespa and Polistes of the temperate zone. The



154 HYMENOPTERA.

genus Nectarina is a short plump wasp, somewhat like Odyne-
rus in shape ; its distinguishing mark is the concealment of
the postscutellum by the scutellum. Nectarina mellifica Say,
of Mexico, builds a large nest externally like that of a wasp,
but it is more irregular, and the papery covering consists of
but one layer. The interior of the nest is very different, the
galleries of cells, instead of being parallel, being arranged in
concentric spheres.

Chartergus has the tip of the clypeus slighted excavated, and
an oval sessile abdomen. C. chartarius Olivier makes an ex-
ceedingly thick tough nest, attached by a broad base to the
bough of a tree, about twice as long as thick, and ending in a
cone, pierced in the centre by the entrance which passes
through the middle to the basal gallery ; the other galleries are
formed by a continuation of the sides of the nest, and arrayed
in a conical plane.

In Tatua, the abdomen is pedicelled, but the petiole is not
enlarged, and the abdomen itself is very regularly conical. T.
morio Cuvier, from Cayenne, forms a nest like that of Charter-
gus ; but the galleries form a flat floor, and each gallery has an
entrance from the outside of the nest, where in the latter there is
one common entrance. Plate 5, Fig. 9, shows how the bases
of the cells are laid out on the edge of a galleiy. In Synonca
the peculiarly shaped abdomen is cordate and compressed. The
curious nest of S. cyanea Fabr. is formed of a single layer of
cells fixed against the trunk of a tree, and covered in with a
dense covering made from the bark of dead trees. Some nests
of Synoeca are three feet long. In the very extensive genus
Polybia, which resembles Polistes in its general shape, the abdo-
men is pedicelled, and the mandibles are four-toothed. The nests
are somewh'at like those of Chartergus, but much smaller. Sev-
eral species occur in Mexico, and in Brazil the number of
species is very great. In Apo'ica the abdomen is very long,
and the third segment is as long as the second. Plate 5, Fig.
11, represents the nest of Apo'ica pallida Olivier, from Cayenne.
It is unprotected, with a conical base, and with a single row
of cells.

In Icaria we have an approach to Polistes in the slender
series of cells composing the nest, forming two or three rows



VESPARI^E. 155

only. Plate 5, Fig. 7, represents the nest of I. guttatfpennis
Saussure, from Senegal ; 8, ground plan of a similar nest. These
wasps are mostly distinguished from Polybia by the petiole
ending in a globular mass. Plate 5, Fig. 10, represents
the elegant nest of Miscliocyttarus labiatus Fabr., from Cay-
enne and Brazil, which consists of a few cells supported by a
long pedicel. The wasp itself much resembles Polistes, but
the petiole is very much longer.

The remaining genera noticed here are solitary, building
separate cells, and with only males and females. There are
three subcostal cells in the fore wings, and the maxillae and
labium are much elongated.

In Eumenes the abdomen has a long pedicel, being sessile in
Odynerus. While authors place Eumenes higher than Ody-
nerus, we would consider the latter as a higher, more cepha-
lized form, since the abdomen is less elongated, and the head
is larger.

In Odynerus the ligula is long, deeply forked at the
slender extremity, while the slender paraglossa* are shorter,
ending in a two-toothed claw-like tip ; the maxillae are slender,
and the palpi have an elongated basal joint ; the clypeus is
nearly circular, toothed on the front edge. The larva differs
from those of the higher Ve spar ice , in its more elongated head,
the square clypeus, the unusually deep fissure of the bilobate la-
brum, and in the larger tubercles of the body, as the larva is
more active, turning and twisting in its cell, while feeding on
its living food ; and in this respect it is more closely allied to
the young Crabronidce. In the pupa of 0. cdbophaleratus,
the tip is more incurved than in the pupa of Vespa, so that the
hind legs (tarsi) reach to the tip, and the abdomen is rounded
ovate, while in Vespa it is oblong.

The cells (Plate 4, Figs. 13, 14) of Odynerus albophcderatus
Sauss. have been detected like those of Osmia in a deserted gall
of Diplolepis confluens, where several were found in a row,
arranged around one side of the gall, side by side, with the holes
pointing towards the centre of the gall. The cells are half an
inch long, and one-half as wide, being formed of small pellets
of mud, giving a corrugated, granulated appearance to the
outside, while the inside is lined with silk.



156 H YMENOPTERA .

>

We have received from Mr. Angus deserted cells of Cera-
tina in a syringa stem, in which we detected a pupa of an
Odynerus, perhaps 0. leucomelas ; the cell was a little shorter
than that of the Ceratina it had occupied. The cocoon of
the Odynerus was of silk, and almost undistinguishable from
the old cocoon of Ceratina. The wasp had dispensed with the
necessity of making a mud cell. If future research shows that
either this or any other species makes a mud cell or not at
will, it shows the intelligence of these little "free-agents;"
and that a blind adherence to fixed mechanical laws does not
obtain in these insects.

The larvae of Odynerus and Eumenes are carnivorous. I
found several cells of 0. alboplialeratus, June 22d, in the
deserted nest of a Clisiocampa, which were stored with micro-
lepidopterous larvae and pupae, still alive, having been para-
lyzed by the sting of the wasp. The larvae of the wasp was
short and thick, being, when contracted, not more than twice
as long as broad ; the rings of the body are moderately convex,
and the pleural region is faintly marked. Prof. A. E. Verrill
has discovered the cells of an Odynerus at New Haven, forming
a sandy mass (Plate 5, Fig. 12) attached to the stem of a
plant.

In Eumenes the lingua is very long, being narrower and
more deeply divided than in Odynerus ; the second subcostal
space of the wings is long and narrow, while in Odynerus it is
triangular. The genus is easily recognized by the very long
pedicel of the abdomen. Eumenes fraterna Say constructs a
thin cell (Plate 5,* Fig. 15) of pellets of mud, and as large

* EXPLANATION OF PLATE 5. Fig. 1. Mouth of the tunnel of Augoclilora pnrus ,-
from Emevton. Fig. 2. Cells of Osmia pacifica ; communicated by Mr, Sanborn.
Fig. 3. Vertical section of nest of Vespa with a group of primitive cells surrounded
by one layer of paper, and part of another; from Saussure. Fig. 4. Nest of Po-
listes annularis ; from Saussure. Fig. 5. Three primitive cells of Polistes; 5, top
view of the same, one being eggless. The sides adjoining are angular. Figs. (5 and
6 a, a cell farther advanced, consisting of four cells, each containing an eerg, and
with the edges of the cells built up higher and more decidedly six-sided; original.
Fig. 7. Cells of Icaria gnttatipennis, showing that each cell is built up independently
in regular hexagons. Fig. 8. Ground plan of a similar nest. Fig. !). Ground plan
of cells of Tatua ntorio ; from Smith. Fig. 10. Nest of Miscliocyttarus labiatus ;
from Saussure. Fig. 11. Nest of Apo'ica pallida ; from Saussure. Fig. 12. Nest of
Odynerus: original. Fig. 13. Nest of Odynerus albophaleratus ; original. Fig. 14.
Mud cell of Pelopceus flavipes ; original. Fig. 15. A row of spherical cells of Eu-
menes fraterna, with the female; original, from Harris.



CRABKONID^E. 157

as a cherry. It is attached by a short stout pedicel to bushes,
and the cavity is filled with the larvae of small moths.

Raphiylossa odyneroides, from Epirus, described by S. S.
Saunders, makes elongated cells in galleries in briars, storing
them with the larva! of what he supposed to be weevils. The
dark brown dense tough cocoon of a Chrysis was also found in
the cells.

In Masons, which connects the Ve s p a r i ce with the succeed-
ing family, the wings are not completely folded when at rest ;
there are but two subcostal cells ; the maxillae are rudimen-
tary ; and the antennae are clavate and eight-jointed. Masuris
vespoides Cresson, inhabits Colorado Territory.

CRABRONID^E Latreille. Sand-wasps, Wood-wasps. In the
more typical genera the head is remarkably large, cuboidal,
while the clypeus is very short, and covered for the most part
with a dense silvery or golden pile. The antennae are genicu-
late, the long second joint being received, when at rest, in a
deep frontal vertical groove ; the mandibles are large, and of
even width throughout, and the mouth-parts are rather short,
especially the lingua, which is often, however, well developed.
There is only one subcostal cell, except in the Philanthince.
The thorax is sub-spherical, and the abdomen is either short
and stout, or more or less pedicellate. The forefeet are
adapted for digging and tunnelling, the forelegs in the females
being broad and flat, and in the males, which are supposed to
do no work, they are sometimes, as in C.Thyreopus, armed with
vexhillate expansions.

The. larva is rather short and thick, a little flattened on the
under side, but much rounded above ; the segments are convex
above, the thoracic segments differing from the abdominal seg-
ments in not being thickened posteriorly on each ring.' They
spin either a very slight cocoon, or a thin dense brown oval
cylindrical case, generally reddish brown in color. The pupae
have much the same character as the imago, with prominent
acute tubercles above the ocelli.

The members of this family afford, so far as we are ac-
quainted with their habits, most interesting examples of the
interdependence of structure and the habits of insects. Most



158 HYMENOPTERA.

of the species are wood-wasps, making their cells in cy-
lindrical holes in rotten wood, or enlarging nail-holes in
posts, as is the case with Crabro singularis, according to the
observations of Mr. C. A. Shurtleff, thus adapting them to the
requirements of their young. Other genera (Rhopalum pedicel-
latum, Stigmus fraternus, and Crabro stirpicola) avail them-
selves of those plants whose stem has a pith which they can
readily excavate and refit for their habitations. The females
provision their nests with caterpillars, aphidaa, spiders, and
other insects.

This family is most difficult to classify ; it consists rather of
groups of genera, some higher and some lower, though as a
general rule those genera with pedunculate abdomens are the
lowest in the series. In illustration, we regard Stigmus, with
its elongated decephalized body, as inferior to Blepharipus,
which again is subordinate to the more cephalized Crabro,
where the body is shorter, the abdomen sessile, the anterior
part of the body more developed headwards, while its nests
are constructed more elaborately. The genus Psen, for the
same reason, is lower than Cerceris, of which it seems a de-
graded form.

Some of the most useful characters in separating the genera
of this family are to be found in the form of the clypeus, its
sculpturing and relative amount of pubescence or hirsuties ; in
the form and sculpturing of the propodeum (Newman), or tho-
racico-abdominal ring of Newport ; while the tip of the abdo-
men presents excellent generic and also specific characters,
depending on its grooved or flattened shape.

The species of this family are mostly found in the north
temperate zone, being very abundant in North America and in
Europe. The Pemphredonime occur far north in abundance,
while Cerceris occurs farthest towards the tropics.

The subfamily Philanthince includes the three genera, Plii-
lanthus, Eucerceris, and Cerceris. In Philanthus (Fig. 84, wing),
the head is short, transversely suboval, the clypeus longer
than broad, with the first joint of the abdomen nearly as broad
when seen from above as the succeeding one. Our more com-
mon form southward is Pliilantlius vertilabris Say (Fig. 85).
In Europe P. apivorus provisions its nest with honey-bees.



CRABRONlDvE.



159




Fig. 85.




Cresson remarks that Eucerceris (Fig. 8G, fore wing of malt- :
a, female) differs from Cerceris in the venation, which
greatly in the two sexes. E. zonatus Say
occurs in the west.

The species of Cerceris (Fig. 87, wing)
have transversely oblong heads, the front of
the head is flattened and destitute of hairs,
and the rings of the abdomen are contracted,
the middle part being un-
usually convex and coarsely
punctured, while the basal
ring is nearly one-half nar-
rower than the succeeding
ones. Cerceris deserta Say is our most com-
mon form. In Europe some species are Fig. 87.
known to store their nests with bees, and the larvae of Cur-
cnl ion idee and Buprestidce. Dufour unearthed in a sin-
gle field thirty nests of C. bupresticida which were filled with
ten species of Buprestis, comprising four hundred individuals,
and none of any other genus. Cerceris tuberculata provisions
its nest with Leucosomus ophthalmicus ; and C. tricincta with
Clythra.

In the subfamily Crabronince, there is a great disparity in
the sexes, the form of the females being the most persistent.
In the male the head is smaller, narrow behind, with shorter
mandibles, and a narrower clypeus ; the body is also much
slenderer, especially the abdomen, and the legs are simple in
Crabro, but in Thyreopus variously modified by expansions of
the joints, especially the tibia. The
species of Crabro (Fig. 88) are readily
distinguished by the large cubical
head, and the sharp mncronate abdo-
minal tip of the female. The more
typical form of this very extensive
genus is Crabro sex-maculatus Say,
so-called from the six yellow spots

on the subpedunculate abdomen. According to Dr. T. "W.
Harris (MS. notes), this wasp was seen by Rev. Mr. Leonard,
of Dublin, N. H., burrowing in decayed wood, June 10th.




160 HYMENOPTERA.

Crabro singularis Smith, was discovered by Mr. C. A. Shurtleff
boring in a post.

In Thyreopus, the body is slender, and the forelegs are
curiously dilated in the males, often forming a broad expansion,
and so dotted as to present a sieve-like appearance, while the
head is much shorter, being more transverse. T. latipes Smith
is known by the broad, long, acute, mucronate, shield-like ex-
pansion of the fore tibia, which is striped with black, at the
base.

The species of Rhopalum are usually blackish, without the
gay colors prevalent in the genera before mentioned ; the legs
are simple, and the abdomen is long and slender, with a long
peduncle. The body of the larva is short and thick, tapering
rapidly towards each extremity ; the segments are convex,
those of the thorax especially being smooth, broad, and regu-
larly convex, while the abdominal rings are provided with
prominent tubercles. The tip of the body is quite extensible,
and when protruded is subacute, terminating in a small knob-
like body, formed by the last ring. The larvae of this genus
differ from those of the Vesparim audApiarice known to us
by having a few hairs scattered over the body.

In the pupa the antennae, in their natural position, do not
quite reach to the second pair of trochanters, and reach only
to the tip of the maxillary palpi. The tip of the abdomen is
very acute and elongated unusually far beyond the ovipositor.
On the head, between the ocelli and antennae, are two very
prominent, acute tubercles, and the abdominal segments are
dentate on the hind edge. Thus both the larva and pupa
would seem, by their anatomy, to be unusually active in their
loose, illy-constructed cells, which do not confine their food so
closely as in the other wasps, as the insects on which they prob-
ably feed have a greater range in their rather roomy cells. April
18th we opened several stems grown in the open air, and
found both larvae and pupae ; the latter in different stages of
development. The cells were placed in the closely packed
dust made by the larva of an JEgeria, or directly bored in the
pith of the plants. There were six such cells, each with its
inhabitant, within a space an inch in length, some laying cross-
wise, others along the middle. The larvae spin but a very



CRABRONID^E. 161

slight cocoon, not at all comparable with that of Crabro : the
walls of the cell being simply lined with silken threads. Under
other circumstances, i.e. where the cells are more exposed, it
is not unlikely that a more elaborate cocoon may be spun.

Mr. James Angus has bred numerous specimens of Rliopq-
hi i n iH'rtia'lhitum Pack., from stems of the Rose, Corcorus, Ja-
poni'ja, and Spinua, grown in hot-houses at West Farms, N. Y.
The larva is a quarter of an inch long.

The following genera belong to the subfamily Pemphre-



The genus Stigmus, as its name indicates, may at once be
known by the very large pterostigma, as well as the unusually
small size of the species. The body of the larva is moderately
long and slender, cylindrical, tapering slowly towards both ex-
tremities. The rings are short, very convex, subacutely so,
and the larva is of a beautiful roseate color. Stfgmus frater-
nus Say burrows in the stems of the Syringa, of which speci-
mens have been received from Mr. Angus with the larvae and
pupae.

In Cemonus the front narrows rapidly towards the insertion
of the mandibles, and there is a short triangular enclosure on
the propodeum, while the abdomen is shorter and thicker than
in Pemphredon, a closely allied genus ; the pedicel is also
longer. The larvae of Cemonus inornatus Harris live in irregu-
lar burrows in the elder, like those of Rhopalum from which
they have been reared by Mr. Angus. They are known by the
broad flattened head and body, serrate side and tergum of the
body, and large, conspicuously bidentate mandibles, as well as
by the peculiarly flattened abdominal tip.

In Passalvecus the labrum is very prominent, while the man-
dibles are very large, widening towards the tip, and in the com-
mon P. mandibukiris Cresson they are white, and thus very
conspicuous. This species burrows in company with the other
wood-wasps mentioned above in the stems of the elder and
syringa. The cells are lined with silk. The wasps appear
early in June. Their nests are tenanted by Chalcids. The
female stores her cells with Aphides, as we have found them
abundantly in steins of plants received from Mr. Angus.

The genus Psen seems to be a degraded Cercerisf but the
11



162 H YMENOPTER A .