370 



HYBERNATION OP INSECTS. 



we know, from the experience of Sir Joseph Banks and Dr. 

 Solander in Terra del Fuego, as well as from other facts, is 

 felt by man when exposed to a very low temperature ; yield- 

 ing to which, torpidity ensues. Others, admitting that cold 

 is the cause of torpidity, maintain that the sensations which 

 precede it are of a painful nature ; and that the retreats in 

 which hybernating animals pass the winter are selected in 

 consequence of their endeavours to escape from the disagree- 

 able influence of cold. 



I have before had occasion to remark the inconclusiveness 

 of many of the physiological speculations of very eminent 

 philosophers, arising from their ignorance of Entomology, 

 which observation forcibly applies in the present instance. 

 The reasoners upon torpidity have almost all confined their 

 view to the hybernating quadrupeds, as the marmot, dor- 

 mouse, &c, and have thus lost sight of the far more extensive 

 series of facts supplied by hybernating insects, which would 

 often at once have set aside their most confidently-asserted 

 hypotheses. If those who adopt the former of the opinions 

 above alluded to had been aware that numerous insects re- 

 tire to their hybernacula (as has been before observed) on 

 some of the finest days at the close of autumn, they could 

 never have contended that this movement, in which insects 

 display extraordinary activity, is caused by the agreeable 

 drowsiness consequent on severe cold ; and the very same fact 

 is equally conclusive against the theory that it is to escape the 

 pain arising from a low temperature that insects bury them- 

 selves in their winter quarters. 



In fact, the great source of the confused and unsatisfactory 

 reasoning which has obtained on this subject is, that no au- 

 thor, as far as my knowledge extends, has kept steadily in 

 view, or indeed has distinctly perceived, the difference be- 

 tween torpidity and hybernation; or, in other words, be- 

 tween the state in which animals pass the winter, and their 

 selection of a situation in which they may become subject to 

 that state. 



That the torpidity of insects, as well as of other hyber- 

 nating animals, is, with us, caused by cold, is unquestionable. 

 However early the period at which a beetle, for example, 



