432 HYBERNATION OF INSECTS. 



comparatively few in number, seems proved from two 

 considerations : first, That the majority of insects as- 

 sume the imago, and deposit their eggs in the summer 

 and early part of autumn, when the heat suffices to hatch 

 them in a short period : and secondly. That the eggs 

 of a very large proportion of insects require for their 

 due exclusion and the nutriment of the larvae spring- 

 ing from them, conditions only to be fulfilled in sum- 

 mer, as all those which are laid in young fruits and. 

 seeds ; in the interior and galls of leaves ; in insects 

 that exist only in summer, &c. &c. The insects which 

 pass the winter in the egg state are chiefly such as 

 have several broods in the course of the year, the fe- 

 males of the last of which lay eggs that, requiring 

 more heat for their development than then exists, ne- 

 cessarily remain dormant until the return of spring. 



The situation in which the female insect places her 

 eggs in order to their remaining there through the 

 w inter, is always admirably adapted to the degree of 

 cold which they are capable of sustaining ; and to the 

 ensuring a due supply of food for the nascent larvae. 

 Thus, with the former view, Gri/llus verrucivorus and 

 many other insects whose eggs are of a tender con- 

 sistence, deposit them deep in the earth out of the 

 reach of frost ; and with the latter, Bombi/x Neustria, 

 B. castrensis, B. dispar, and some other moths, de- 

 parting from the ordinary instinct of their congeners, 

 which teaches them to place their eggs upon the leaves 

 of plants, fix theirs to the stem and branches only. 

 That this variation of procedure has reference to the 

 hybernation of the eggs of these particular species, is 

 abundantly obvious. Insects whose eggs are to be 



