AMERICAN ENTOMOLOGY. 47 



slightly compressed, not obliquely truncated ; oviduct concealed, 

 or hardly prominent. 



Ohs. As originally instituted by Linne, the genus of this name 

 was extremely abundant in species, and although many divisions 

 have been made by Fabrieius and others, the species are still 

 numerous. As" I adopt the genus, it corresponds with that of 

 Fabrieius and Latreille, and with Cri/ptus as defined by Lamarck, 



These insects perform an important part in the operations of 

 nature, inasmuch, as they seem destined to limit the increase of 

 Lepidopterous insects, by destroying their larvae, so injurious to 

 the interests of agriculture. All are parasitic, and in habit they 

 may be compared to the Ichneumon amongst the quadrupeds, an 

 animal said to break the eggs of the crocodile, and even to pene- 

 trate the abdomen of that formidable reptile, in order to devour 

 the living viscera. 



The female, in this interesting genus, when about to deposit 

 her eggs, becomes very active and impatient, flying from leaf to 

 leaf, in search of a proper nidus ; having found a caterpillar of 

 suitable magnitude, she places her eggs either upon the skin, or 

 by puncturing it, within the body, notwithstanding the convul- 

 sive eiForts of prevention made by the victim. I was witness to 

 a somewhat curious fact in relation to one of these insects ; ob- 

 serving an object closely resembling a caterpillar, resting on a 

 leaf, I was preparing to take possesion of it, when an Ichneumon 

 alighted on the leaf, and proceeded to examine the object of my 

 attention ; it ran briskly up to it, and touched it first on one side, 

 and then on the other, with its vibratory antenna) ; but it finally 

 departed without any attempt at ovipositiou. This deportment 

 excited my suspicions in regard to the nature of the supposed 

 caterpillar, and on examining it more closely, I discovered, to 

 my surprise, that it was not the larva of an insect, nor even the 

 remains of one. Thus it appeared, that the Ichneumon, as well 

 as myself, was deceived by its organ of vision, and that another 

 sense was resorted to, in order to ascertain the truth. 



The larvae disclosed from the eggs of the parent Ichneumon, 

 are altogether destitute of feet ; like intestinal worms, they feed 

 on the interior of the body of their Promethean victim, which 

 continues to walk and feed as usual. The depredators are by no 

 means indiscriminate in their choice of food, but prefer the 



