210 



PRODUCTIVE FARMING 



group (Fig. 127). This is a common form in the South. 

 The bodies of the insects are striped with bands of black 

 and white. By removing the breeding places of these insects 

 the yellow fever disease has at times been stamped out in 

 New Orleans and elsewhere. 



Exercise. — To Study Mosquito Wrigglers. — Put a glass 

 of water from a rain barrel, with a few wrigglers in it, on a 

 window sill. Cover it with a sheet of wire gauze to catch any 

 that transform. Observe the breathing tubes that are held 

 up to the surface of the water when the wrigglers are at rest. 



Fig. 127. — The yellow-fever mosquito, larva, pupa, adult. (From Smith's " 

 Friends and Enemies.") 



Insect 



Flies. — The eggs of flies are laid in moist masses of decay- 

 ing refuse, such as manure, dead animals, slop, and many 

 kinds of garbage. When the eggs hatch the maggots use 

 those materials as food and grow rapidly. Then they cover 

 themselves with a leather-like pupa case, from which they 

 emerge in a few days as adult flies (Fig. 128). The time 

 required for the eggs to develop into adult flies is only a 

 few days. A few of the adult flies live over winter and these 

 are the ones that start the first broods when warm weather 

 returns. By the end of the summer the number of flies 

 has increased enormously. 



