CHAPTER III. 



LIFE BEGINS IN THE EGG. 



THE eggs of birds are, in most instances, hatched 

 by the warmth of the mother, who sits for a cer- 

 tain time covering them with her wings and 

 downy breast. But the exception to the rule in 

 insects is that the mother has anything to do with 

 rearing her young brood ; the cases in which this 

 takes place will be noticed in our next chapter. 

 Generally speaking, the eggs of insects are hatched 

 by the increasing temperature of the air in spring. 

 The following sketch, extracted from Mr. Darwin's 

 interesting Journal of the Voyage of the Beagle, 

 sets before us, in a very pleasing manner, the 

 awakening influence of this season to all nature : 

 "When we first arrived at Bahia Blanca, Sep- 

 tember 7th, 1832, we thought nature had granted 

 scarcely a living creature to this dry and sandy 

 country. By digging, however, in the ground, 



