THE ICHNEUMON FLY. 131 



in order to leave their fatal present in its body; 

 the caterpillar, the gnat, and even the spider him- 

 self, so formidable to others, is often made the 

 unwilling fosterer of this destructive progeny. 



About the middle of summer, when other in- 

 sects are found in great abundance, the ichneu- 

 mon is seen flying busily about, and seeking pro- 

 per objects upon whom to deposit its progeny. As 

 there are various kinds of this fly, so they seem 

 to have various appetites. Some are found to 

 place their eggs within the aurelia of some nascent 

 insect, others place them within the nest which 

 the wasp had curiously contrived for its own 

 young ; and as both are produced at the same 

 time, the young of the ichneumon not only de- 

 vours the young wasp, but the whole supply of 

 worms which the parent had carefully provided 

 for its provision. But the greatest number of the 

 ichneumon tribe are seen settling upon the back 

 of the caterpillar, and darting, at different inter- 

 vals, their stings into its body. At every dart 

 they deposit an egg, while the wounded animal 

 seems scarcely sensible of the injury it sustains. 

 In this manner they leave from six to a dozen of 

 their eggs within the fatty substance of the rep- 

 tile's body, and then fly off to commit further 

 depredations. In the mean time the caterpillar, 

 thus irreparably injured, seems to feed as vora- 

 ciously as before, does not abate of its usual acti- 

 vity, and, to all appearance, seems no way affect- 

 ed by the internal enemies that are preparing its 

 destruction in their darksome abode.. But they 

 soon burst from their egg state, and begin to prey 



