918 INSECTA. 
positor is very short, and but slightly or not at all apparent, deposit 
their ova in the body of larvee, caterpillars, and nymphs, which are 
exposed or very accessible. 
The larvee of the Ichneumonides, like all the others of the suc- 
ceeding families, are destitute of feet. Those which, in the manner 
of intestinal worms, inhabit the bodies of larve or caterpillars, where 
they sometimes form communities, only attack the adipose substance 
—corps graisseux—or such of the internal parts as are not necessary 
to their existence. When about to become nymphs, however, they 
perforate their skin in order to open a passage, or put them to death, 
and there tranquilly undergo their ultimate metamorphosis, Such 
also are the habits of those which feed on nymphs or chrysalides, 
Nearly all of them spina silken cocoon, in which they become nymphs. 
These cocoons are sometimes agglomerated, either naked, or en- 
veloped in a sort of tow or cotton, in an oval mass, frequently found 
attached to the stems of plants. The symmetrical arrangement of 
flie cocoons of one species forms an alveolar body, resembling the 
honeycomb of our domestic Bee. The silk of these cocoons is some- 
times of a uniform yellow or white, and sometimes mixed with black 
or filaments of two colours. Those of some species are suspended to 
a leaf or twig, by means of a long thread. Reaumur has observed 
that when detached from the bodies to which they are fixed, they 
make repeated jumps to about the height of four inches, the larva 
enclosed in the cocoon approximating the two extremities of its body, 
and then suddenly returning to a straight line in the manner of 
various skipping larve of Dipterous Insects, found on old cheese. 
This family is extremely rich in species. 
The difference in the number of joints found in the palpi may 
serve as a hasis of three principal divisions. 
The first will comprise those species in which the maxillary palpi 
have five joints, and the labials four. The second cubital cell is very 
small, and, almost circular or null. 
We will form a first subdivision with those in which the head is 
never prolonged anteriorly in the form of a snout or rostrum, in 
which the ligula is not deeply emarginated, and in which the max- 
illary palpi are much elongated, their last joints, in form and pro- 
portion, differing evidently from the preceding ones. The ovipo- 
sitor is not covered at base by a large lamina in the form of a 
-vomer. 
Here, this ovipositor is extremely salient. 
Some species are distinguished from the others by their almost 
globular head, their mandibles terminated in an entire or but slightly 
emarginated point, and by the elongation of their metathorax. The 
Eerone cubitalcell is frequently wanting. Such are those which form 
the 
STEPHANUs, Jur.—PimpiA, Bracon, Fab., 
Where the thorax is much thinned anteriorly, and on a level at its 
posterior extremity with the origin of the abdomen, so that this part 
of the body appears almost sessile and inserted in the posterior and 
superior extremity of the thorax as in the Eyanie. ‘The posterior 
