HIBERNATION OF INSECTS. 4,53 



ing in a different manner. Some conceive that cold 

 combined with a degree of fatness arising from abun- 

 dance of food in autumn, produces in them an agreeable 

 sensation of drowsiness, such as we know, from the ex- 

 perience 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; yielding 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 

 disagreeable influence of cold. 



I have before had occasion to remark a the inconclu- 

 siveness 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 qua- 

 drupeds, as the marmot, dormouse, &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 retire 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 drow- 

 siness consequent on severe cold ; and the very same 

 fact is equally conclusive against the theory, that it is to 

 * VOL. I. 32. 



