i88 THE ANIMALS AND MAN 



favorite breeding-places, which are manure piles and privy 

 vaults. The eggs are laid on fresh manure or excrement 

 and hatch in from eight to twelve hours into footless mag- 

 gots that reach their full growth in as few as eight days. 

 Then they change to pupae from which the adult flies issue 

 in from eight to eighteen days. The length of life in the 



Fig. 93. Foot of house-fly showing claws, hairs, pulvilli and the minute 

 clinging hairs on the pulvilli. (Photograph by R. W. Doane.) 



different stages, egg, larva, and pupa, varies with tempera- 

 ture and other conditions. All manure should be removed 

 from barnyards at least once a week and spread out to dry. 

 The flies cannot breed in dry manure. If the manure 

 cannot be removed and spread out it should be keptjn a fly- 

 tight bin. Outdoor privy vaults and cesspools must be 

 attended to. Cesspools should be kept covered and all pit 

 privies replaced by dry-earth closets. Finally garbage 

 cans and rubbish heaps should be cared for. Of course. 



