44 GRAMMAR OF ENTOMOLOGY. 



135. The chrysalis state lasts but a few 

 days, and the perfect insect emerges from it ; 

 after this first escape, it has to penetrate the 

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

 it is still imprisoned, and which is made much 

 harder by the drying of the portions of animal 

 matter which the maggot of the ichneumon had 

 left unconsumed. 



136. 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 immediately on emerging, the ichneumon 

 vibrates its wings and flies away. 



137. The caterpillar of the tiger-moth is 

 preyed on in a similar manner by the maggot 

 of a two-winged fly ; and this maggot, 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. 



138. 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 cater- 

 pillar, and does not perforate the skin, and deposit 

 it inside, as in the case of the great ichneumon 

 before described, it is supposed the small ichneu- 

 mon's egg is laid in the egg of the fly while the 

 latter is adhering to the skin of the caterpillar. 



