HYMENOPTERA. 217 
legs. The antenne are generally filiform or setaceous, rarely clavate, 
vibratile, and multiarticulated, being composed of sixteen joints at 
least. In most of them the mandibles have no tooth cn the inner 
side, and terminate in a bifid point. The maxillary palpi, always 
apparent or salient, consist most commonly of but five joints. The 
ovipositor is formed of three threads. 
This tribe embraces almost the whole genus 
Icuneumon, Lin.* 
These Insects destroy the posterity of the Lepidoptera, so noxious 
to the agriculturalist under the form of caterpillars, just as the quad- 
rupcd so called is said to destroy that of the Crocodile by breaking 
its eggs, and even by introducing itself into the body of the animal, 
in order to devour its entrails. 
Some authors have called them Mouches tripifles, on account of the 
three setze which compose their ovipositor, and Mouches vibrantes, 
because their antenne are continually vibrating. These organs are 
frequently curled (contournées), and have a white or yellowish an- 
nular spot in the middle. Their maxillary palpi are elongated, 
almost setaceous, and consist of from five to six joints; the labials 
are shorter, filiform, and have but from three to four joints. The 
ligula is usually entire or simply emarginated. The body is most 
frequently narrow and elongated or linear, with the ovipositor 
sometimes exterior and resembling a tail, and sometimes very shert 
and concealed in the interior of the abdomen, which then terminates 
in a point, whilst in those where the ovipositor is salient it is thicker, 
and as if clavate and truncated posteriorly. Of the three pieces 
which compose this instrument the intermediate is the only one 
that penetrates into the bodies in which these Insects deposit their 
eggs; its extremity is flattened, and sometimes resembles the nib of 
a pen. 
The females, anxious to lay, are continually flying or walking 
about |, in order to discover the larvee, nymphs, and eggs of Insects, 
and even Spiders, Aphides, &c., destined to receive their ova, and 
when hatched, to sustain their offspring. In this search they exhibit 
a wonderful degree of instinct, which reveals to them the most secret 
retreats of its objects. Those which are provided with a long ovipo- 
sitor deposit the germs of their race in the fissures or holes of trees, 
or under their bark, In this operation the ovipositor proper is intro- 
duced 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 ovi- 
* This genus comprises upwards of twelve hundred species, and its study is ex- 
tremely difficult. The labours of MM. Gravenhorst and Nées de Esenbeck have 
rendered it somewhat easier. The former of these gentlemen has lately published 
the prospectus of a complete work on these Insects, and we have every reason to 
believe that this interesting portion of entomology will be henceforward as well un- 
derstood as the state of the science will allow. 
+ Some species are apterous or have but very short wings. They are the subject 
of a particular Monograph, published by M. Gravenhorst, who has also furnished 
us with another on the Ichneumons of Piemont, 
VOL, IY. Q 
