HYBERNATION OF INSECTS. 



373 



determination to explain every thing, led to promulgate. But 

 in truth there was no absolute need for imposing this fatigue 

 upon your attention; for the single notorious consideration 

 that in this climate, as well as in more southern ones, we not 

 unfrequently have sharp night-frosts in summer, and colder 

 weather at that season than in the latter end of autumn and 

 beginning of winter, and yet that insects do hybernate at 

 the latter period, but do not at the former, is an ample refut- 

 ation of the notion that mere cold is the cause of the pheno- 

 menon. If, indeed, the hybernacula of insects were simply 

 the underside of any dead leaf, clod, or stone that chanced 

 to be in the neighbourhood of their abode, it might still be 

 contended, that such situations were always resorted to by 

 them on the occurrence of a certain degree of cold, but that 

 they remained in them only 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 animals, to which they have exclusively directed 

 their attention. 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 one half or three 

 fourths 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 habitations requiring 

 considerable time and labour, expressly 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 

 doAvn and sleep ; but we should laugh at any one who con- 

 tended 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 ces- 

 sation of cold to quit them. But, as has been before observed^ 



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