398 



GENERAL SCIENCE 



is due to the quantity of food eaten during the growing 

 period. After the fly has been in the adult stage for two 

 or three days, eggs are again deposited, making a complete 

 generation in from 12 to 16 days. It is possible to have as 

 rrany as eight or ten generations of flies in one summer. 



The house fly can 

 easily be destroyed by 

 removing or covering 

 all places where it is in 

 the habit of depositing 

 eggs, thus preventing 

 their production. It 

 can also be destroyed 

 in the adult stage by 

 poisons and traps and 

 various other means 

 which man has devised 

 for the purpose. 



275. Mosquitoes. - 

 The life history of the 

 mosquito is similar to 

 that of many other 

 insects. Their eggs are 

 laid on water and in a 



(a) Raft of eggs, (b) Eggs enlarged. , , hutrh 



(c) Larvae or wrigglers, (d) and (e) are da y r SO tne y natctl 



larvae enlarged. (/) Pupa; (g) and (ti) and the larvae emerge. 



are females, (f) is a male. The Iarv2 feed upon 



bacteria in the water, and in a few days they change 

 from the larva stage to the pupa stage. The larvae 

 are commonly known as wrigglers and hang under 

 the surface of the water with their heads downward, 

 breathing through a tube in their posterior end, which 

 they extend just above the surface of the water. If 



LIFE HISTORY OF THE MOSQUITO 



