HYMENOPTERA. 95 
filiform or setaceous, rarely clavate, vibratile, and multiarti- 
culated, being composed of sixteen joints at least. In most of 
them the mandibles have no tooth on the inner side, and ter- 
minate in a bifid point. The maxillary palpi, always appa- 
rent or salient, consist most commonly of but five joiats. The 
Ovipositor is formed of three threads. 
This tribe embraces almost the whole genus 
Icuneumon, Lin.(1) 
These Insects destroy the posterity of the Lepidoptera, so noxious 
to the agriculturalist under the form of caterpillars, just as the quad- 
ruped 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. f 
Some authors have called them Mouches tripiles, on account of the 
three sete 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 
- short 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 de- 
posit their eggs; its extremity is flattened, and sometimes resem- 
bles the nib of a pen. 
The females, anxious to lay, are continually flying or walking 
about(2), in order to discover the larve, nymphs, and eggs of In- 
(1) 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 pub- 
lished 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 understood as the state of the science will allow. 
(2) 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 
favoured us with another on the Ichneumons of Piemont. 
