198 OUR HOUSEHOLD INSECTS 



influence tending towards shortness of larval life, we 

 may no doubt reckon the fact of the great abundance 

 of food amidst which the larvse find themselves imme- 

 diately on being hatched ; they have literally nothing to 

 do but to eat. No exertions of their own are necessary 

 to procure food; it is all ready to hand. And, again, 

 the condition in which the food is found putrefaction 

 having probably already set in necessitates haste if the 

 grubs are to anticipate the ordinary chemical processes 

 of nature, and seize upon the food material while it is 

 still in tjie condition of organic compounds, and before 

 it has passed into the greater simplicity of combination 

 which restores it to the inorganic world and renders it 

 unfit to support animal life. The eggs, therefore, are 

 hatched very soon after being laid, only a few hours 

 intervening between their deposition and the appearance 

 of larvse. The eggs of the flesh-fly above mentioned 

 (Sarcophaga) are, indeed, hatched before they are laid, 

 i.e., while still in the abdomen of the mother, so that 

 they are laid as living maggots ready at once to com- 

 mence the work of their life. Most of these flies, too, 

 are gifted with extraordinary fecundity, a fact which, 

 while it adds to the annoyance we receive from the 

 perfect insects, at the same time considerably increases 

 the counterbalancing benefits conferred on the world at 

 large by the continued and extensive consumption of 

 putrefying matter. 



The eggs are of a long oval shape, opaque, and of a 

 dull chalky colour. Great numbers are laid in a single 

 batch ; a solitary house fly, which had been enclosed in 

 a bottle, was observed by Dr. Packard to lay 120 eggs 

 in the course of fourteen hours. These were depo- 

 sited in piles, or stacks, loosely at the bottom of the 

 bottle. Twenty-four hours after the completion of the 



