78 METAMORPHOSES. 



doubtless had the wisest ends in view, although we are 

 incompetent satisfactorily to discover them. Yet one 

 reason for this conformation may be hazarded. A very 

 important part assigned to insects in the economy of 

 nature, as I shall hereafter show, is that of speedily re- 

 moving superabundant and decaying animal and vege- 

 table matter. For such agents an insatiable voracity is 

 an indispensable qualification, and not less so unusual 

 powers of multiplication. But these faculties are in a 

 great degree incompatible. An insect occupied in the 

 work of reproduction could not continue its voracious 

 feeding. Its life, therefore, after leaving the egg, is di- 

 vided into three stages. In the first, as larva, it is in a 

 state of sterility ; its sole object is the satisfying its in- 

 satiable hunger ; and, for digesting the masses of food 

 which it consumes, its intestines are almost all stomach. 

 This is usually by much the longest period of its ex- 

 istence. Having now laid up a store of materials for 

 the development of the future perfect insect, it becomes 

 a pupa ; and during this inactive period the important 

 process slowly proceeds, uninterrupted by the calls of 

 appetite. At length the perfect insect is disclosed. It 

 now often requires no food at all; and scarcely ever 

 more than a very small quantity ; for the reception of 

 which its stomach has been contracted, in some instances, 

 to a tenth of its former bulk. Its almost sole object is 

 now the multiplication of its kind, from which it is di- 

 verted by no other propensity ; and this important duty 

 being performed, the end of its existence has been an- 

 swered, and it expires. 



It must be confessed that some objections might be 

 thrown out against this hypothesis, yet I think none that 



