HISTORY OF INSECTS. 9 



would ensure its own death, as it could not subsist on the 

 putrifying carcass. After lying quiescent for some weeks, 

 and frequently through the entire winter, the skin of the 

 maggot is thrown off, and it becomes a chrysalis, exhibiting 

 very nearly the shape and appearance of the future fly ; 

 the antennae and legs being placed before it, the wings 

 small and folded by its side, and the ovipositor being 

 turned up a little over its back. The chrysalis is without 

 motion, and much resembles that of the bee : in both in- 

 stances the limbs are quite distinct from the body, and not 

 united with it in a hard crustaceous cover as is the case in 

 the chrysalis of the silk-worm : this kind of chrysalis is said 

 to be necromorphous, because its limbs are rigid, formally 

 arranged and perfectly motionless, as in death. 



The chrysalis state lasts but a few days, and the perfect 

 insect emerges from it ; after this first escape, it has to pe- 

 netrate the shell of the chrysalis of the tiger-moth, in which 

 it is still imprisoned, and which is rendered much harder by 

 the drying of the portions of animal matter left uncon- 

 sumed by the maggot of the ichneumon. The ichneumon 

 overcomes this difficulty by gnawing a hole, with its sharp 

 and strong jaws, generally in that thin portion of the shell 

 which covers the wing of the future insect : almost imme- 

 diately on emerging, the ichneumon vibrates its wings, and 

 flies away. 



The caterpillar of the tiger-moth is preyed on in a similar 

 manner by the maggot of a two-winged fly ; and this mag- 

 got, while thus devouring the interior of the caterpillar, is 

 itself a prey to a minute kind of ichneumon, twenty of which 

 sometimes feed in the maggot of a single fly. The manner 

 in which the egg of this little ichneumon is introduced into 

 the maggot of the fly, is at present unknown ; but as the fly 

 fastens its egg exteriorly on the skin of the caterpillar, and 

 does not perforate the skin to deposit it inside, as in the 



