HYBERNATION OF INSECTS. 463 
when its continuance had induced torpidity : and it seems 
to have been in this view that most reasoners on this 
subject have regarded the hybernation of the larger ani- 
mals, to which they have exclusively directed their at- 
tention. But had they been acquainted (as surely the 
investigators of such a question ought to have been) with 
the economy of the class of insects, in which not merely 
a few species, as among quadrupeds, but ninety-nine 
hundredths of the whole, in our climates, hybernate, they 
would have known that their hybernacula are in general 
totally distinct from their ordinary retreats in casual 
cold weather; and that many of them even fabricate ha- 
bitations requiring considerable time and labour, ex- 
pressly for the purpose of their winter residence—which 
last fact in particular, on their theory, admits of no 
satisfactory explanation. We may say, and truly, that 
the sensation of fatigue causes man to lie down and 
sleep; but we should laugh at any one who contended 
that this sensation forced him first to make a four-post 
bedstead to repose upon. 
In the second place, if we grant for a moment that it is 
cold which drives insects to their hybernacula, there are 
other phenomena attending the state of hybernation 
which on this supposition are inexplicable. If cold led 
insects to enter their winter quarters, then they ought to 
be led by the cessation of cold to quit them. But, as has 
been before observed, we have often days in winter milder » 
than at the period of hybernating, and in which insects 
are so roused from their torpidity as to run about nimbly 
when molested in their retreats; yet though their irrita- 
bility must have been increased by a two or three months 
