96 INSECTA. 
sects, and even Spiders, Aphides, &c., destined to receive their ova, 
and when hatched, to sustain their offspring. In this search they ex- 
hibit a wonderful degree of instinct, which reveals to them the most 
secret retreats of its objects. ‘Those which are provided with along 
ovipositor deposit the germs of their race in the fissures or holes of 
trees, or under their bark. In this operation the ovipositor proper 
is introduced almost perpendicularly, and is completely disengaged 
from its semi-scabbards, which remain parallel to each other, and 
supported in the air, in the line of the body. Those females in 
which the ovipositor is very short, and but slightly or not at all ap- 
parent, deposit their ova in the body of larve, caterpillars, and 
nymphs, which are exposed or very accessible. 
The larve 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, how- 
ever, they perforate their skin in order to open a passage, or put 
them to death, and there tranquilly undergo their ultimate metamor- 
phosis. Such also are the habits of those which feed on nymphs or 
chrysalides. Nearly all of them spin a silken cocoon, in which they 
become nymphs. These cocoons are sometimes agglomerated, 
either naked, or enveloped in a sort of tow or cotton, in an oval mass, 
frequently found attached to the stems of plants. The symmetrical 
arrangement of the cocoons of one species forms an alveolar body, 
resembling the honeycomb of our domestic Bee. The silk of these 
cocoons is sometimes of a uniform yellow or white, and sometimes 
mixed with black or filaments of two colours. Those of some spe- 
cies 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 1 the palpi, may serve 
as a basis 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- 
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