88 NATURE-STUDY REVIEW [12:2— Feb., 1916 



Different Kinds of Flies. How many different kinds of flies do 

 the pupils know? (About 43,000 species are known to science.) 

 How many different kinds can the pupils collect? (Collecting 

 may all be done without so much as touching a fly.) What does 

 each kind do ? 



House Fly, Typhoid Fly, Filth-Disease Fly. This species con- 

 stitutes over 95 per cent, generally, of the flies about homes and 

 is the one that causes most of the annoyance, filth and disease — 

 the one we are chiefly fighting. House flies breed mainly in horse 

 manure, but may do so in any fermenting or rotting vegetable 

 or animal matter. 



Bluebottles , Green Bottles, Big Gray Blow Flics. These flies are 

 scavengers and lay their eggs on meat, but we can dispose of 

 dead animals in more sanitary ways than leaving them to blow 

 flies. They spoil a great deal of fresh fish and meat about our 

 markets and homes. Closely related to the blow flies is the screw 

 worm fly of the South, which lays its eggs in open wounds, the 

 maggots feeding on the living flesh. They also oviposit in catarrhal 

 nostrils or running ears of children or of persons asleep out of 

 doors in the daytime, the maggots causing painful and even fatal 

 wounds. 



Stable Fly. This fly has a sharp proboscis with which it pierces 

 the skin and sucks the blood of animals and man. It breeds in 

 rotting straw or hay or strawy manure. This fly may inoculate 

 the germs of infantile paralysis when it bites. The same germ, 

 it has been claimed, causes limberneck in chickens, and maggots 

 in fowls dead of limberneck may spread the disease to other ani- 

 mals or to man. We should burn all such chickens as soon as 

 any signs of the disease appears, and be careful in handling them. 



Horn Fly. This is the small, dark fly that infests cows and 

 bites, often, by night as well as by day. They often cluster in 

 masses on the horns. They lay their eggs in fresh cow droppings, 

 where they may often be killed by the hundreds with sprays, or the 

 eggs or maggots may be killed by covering the material with lime. 

 This fly was accidentally imported from Europe in 1886 and has 

 since become one of the most serious pests of cattle over the entire 

 continent. 



Black Flies, or Deer Flies, are n pest of fishermen and animals. 

 They breed in running water, often in the waste water about wells 



