6 BRITISH BUTTERFLIES. 



human mothers, and in a round of "butterfly's balls," 

 and such like dissipations, forgets the sacred claims of 

 the nursery. ]STo, she has far other and better excuses 

 for absenting herself from her family ; one of which is, 

 that she usually dies before the latter are hatched ; and 

 if that is not enough, that the young can get on quite 

 as well without her ; for probably she could not teach 

 them much about caterpillar economics, unless, indeed, 

 she remembered her own. infantile habits of lang syne, 

 so totally different from those of her perfected butterfly 

 life. 



The space of time passed in the egg state varies 

 much according to the temperature from a few days 

 when laid in genial summer weather, to several months 

 in the case of those laid in the autumn, and which 

 remain quiescent during the winter, to hatch out in 

 the spring. 



The eggs of butterflies, in common with those of 

 insects in general, are capable of resisting not only 

 vicissitudes, but extremes of temperature that would 

 be surely destructive of life in most other forms. The 

 severest cold of an English winter will not kill the 

 tender butterfly eggs, whose small internal spark of 

 vitality is enough to keep them from freezing under a 

 much greater degree of cold than they are ever sub- 

 jected to in a state of nature. Eor example, they have 

 been placed in an artificial freezing mixture, which 

 brought down the thermometer to 22 below zero a 

 deadly chill and yet they survived with apparent 



