HYBERNATION OF INSECTS. 517 
It is probable that some insects of almost every order hybernate in the 
egg state ; though that these must be comparatively few in number, seems 
proved from two considerations ; first, That the majority of insects assume 
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 larve springing from them, conditions 
only to be fulfilled in summer, 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. The insects which pass the winter in the egg state are 
chiefly such as have several broods in the course of the year, the females 
of the last of which lay eggs that, requiring more heat for their development 
than then exists, necessarily 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 winter, 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 larve. Thus, with the former view, 
Acrida verrucivora 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, Clisiocampa neustria, Lasiocampa castrensis, Hypogymna dispar, 
and some other moths, departing from the ordinary instinct of their con- 
geners, which teaches them to place their eggs upon the /eaves 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 hatched in summer 
usually fix them slightly to the leaves upon which the larve are to feed. 
But it is evident that, were this plan to be adopted by those whose eggs 
remain through the winter, their progeny might be blown away along with 
the leaf to which they are attached, far from their destined food. These, 
therefore, choose a more stable support, and carefully fasten them, as has 
just been observed, either to the trunk or branches of the tree whose young 
leaves in spring are to be the food of the excluded larvae. The latter plan 
is followed by the female of Clisiocampa neustria, which curiously gums her 
eggs in bracelets round the twigs of the hawthorn, &c. But another pro- 
vision is demanded. Were these eggs of the usual delicate consistence, and 
to be attached with the ordinary slight gluten, they would have a poor 
chance of surviving the storms of rain and snow and hail to which for six 
or eight months they are exposed. They are therefore covered with ashell 
much more hard and thick than common ; packed as closely as possible to 
each other; and the interstices are filled up with a tenacious gum, which soon 
hardens the whole into a solid mass almost capable of resisting a penknife. 
Thus secured, they defy the elements, and brave the blasts of winter uninjured. 
The female of Hypogymna dispar, whose eggs have a more tender shell, 
glues them in an oval mass to the stem of a tree (whence the German gar- 
deners call the larvee Stamm-raupe), and then covers them with a warm 
non-conducting coat of hairs plucked from her own body, equally impervious 
to cold and wet. 
Another of those beautiful relations between objects at first sight 
apparently unconnected, which at every step reward the votaries of En- 
tomology, is afforded by the coincidence between the period of the hatching 
In spring of eggs deposited before winter, and of the leafing of the trees 
upon which they have been fixed, and on whose foliage the larva are to 
LL 38 
