98 INSECT TRANSFORMATIONS. 



which amidst the rigours of winter flourish and fruc- 

 tify.'* 



It is remarked by John Hunter that an egg will 

 freeze by a great degree of cold; at the same time 

 there seems to be a living principle which enables it to 

 support cold without destruction, and when once that 

 principle is destroyed, cold more easily operates. An 

 egg was thus frozen by the cold of zero; after thaw- 

 ing and again exposing it to the same degree of cold, 

 it froze seven minutes and a half sooner. A new-laid 

 es2 took an hour to freeze in 15° and 17°, but when 

 thawed, it froze at 25° in half the time.f 



The principle of vitality, therefore, whatever may be 

 the cause, is evidently less easily destroyed in the egg 

 state than in the perfect animal; and therefore the 

 inference that a rigorous winter promises a diminution 

 of insects in the summer succeeding commonly proves 

 erroneous. On the contrary, recorded facts prove 

 that they are sometimes even more abundant than 

 usual after severe frosts. During the present spring 

 of 1830, accordingly, notwithstanding the severe frosts 

 of the preceding winter, we have observed a much 

 greater number of insects, even of the smaller and 

 more delicate kinds [AleijrodeSj Corethra, Mucita, 

 &c,) as well as of larvae, both those just hatched, and 

 those which have lived through the winter, than last 

 year, when the frost was not so severe. We were 

 particularly struck with the larvee of some small 

 tipula {Boletophila?), which we found in abundance 

 in Birch Wood, Kem, feeding on a fungus {Boletus 

 fomentarius^ Fries), and which were so beautifully 

 transparent and soft, that we could not understand 

 how they had escaped being frozen. It is not a 

 little remarkable, in connexion with this, that the 



* Spallanzani's Tracts, transl. by Dalyell, vol. i, p. 63. 

 t Huater on the Animal Economy. 



