DEVELOPEMENT OF INSECTS. .'307 



These successive peelings of the skin are but 

 so many steps in preparation for a more impor- 

 tant change. A time comes when the whole of 

 the coverings of the body are at once cast oft', 

 and the insect assumes the form of a pupa, or 

 chrysalis ; being wrapt as in a shroud, presenting 

 no appearance of external members, and re- 

 taining but feeble indications of life. In this 

 condition it remains for a certain period : its in- 

 ternal system continuing in secret the farther 

 consolidation of the organs ; until the period 

 arrives when it is qualified to emerge into the 

 world, by bursting asunder the fetters which had 

 confined it, and to commence a new career of 

 existence. The worm, which so lately crawled 

 with a slow and tedious pace along the surface 

 of the ground, now ranks among the sportive 

 inhabitants of air ; and expanding its newly ac- 

 quired wings, launches forward into the element 

 on which its powers can be freely exerted, and 

 which is to waft it to the objects of its gratifica- 

 tion, and to new scenes of pleasure and delight. 



Thus do the earlier stages of the developement 

 of insects exhibit a recurrence of those structures 

 which are found in the lowest department of this 

 series of animals. The larva, or infantile stage 

 of the life of an insect, is, in all its mechanical 

 relations, a mere worm. The imago, or perfect 

 state, on the other hand, exhibits strong analogies 

 with the crustaceous tribes, not only in the 



