450 INSECTA. 



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 



ICHNEUMON, Lin.(l) 



These Insects destroy the posterity of the Lepidoptera, so noxious to the 

 agriculturalist under the form of caterpillars, just as the quadruped so call- 

 ed is said to destroy that of the Crocodile by breaking- its egg's, and even 

 by introducing itself into the body of the animal in order to devour its en- 

 trails. 



Some authors have called them Mouches tripiles, on account of. the three 

 setae which compose their ovipositor, and Mouches vibrantes, because their 

 antennae are continually vibrating. These organs are frequently curled 

 (contournees), and have a white or yellowish annular spot in the middle. 

 The body is most frequently narrow and elongated or linear, with the ovi- 

 positor 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 deposit their eggs; its extremity is flattened, and some- 

 times resembles the nib of a pen. 



The females, anxious to lay, are continually flying or walking about, in 

 order to discover the larvae, 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 ovipositor deposit the germs of their race in the 

 fissures or holes of trees, or under their bark. In this operation the ovi- 

 positor proper is introduced almost perpendicularly, and is completely dis- 

 engaged 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 apparent, deposit their 

 ova in the body of larvae, caterpillars, and nymphs, which are exposed or 

 very accessible. 



The larvae of the Ichneumonides, like all the others of the succeeding 

 families, are destitute of feet. Those which, in the manner of intestinal 

 worms, inhabit the bodies of larvae 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 



(1) This genus comprises upwards of twelve hundred species, and its study 

 is extremely difficult. 



