180 SCHOOL ENTOMOLOGY 



the eggs are laid and where the maggots congregate, and 

 sprinkle two or three gallons of water over the treated 

 manure. Such treatment should be given with each addi- 

 tion of fresh manure to the pile, but where it is kept in 

 closed boxes, less frequent treatment will be required. This 

 treatment is cheap and is well worth while. A maggot-trap 

 has also been devised (see 26), for the treatment of horse 

 manure, by which the maggots may be easily and cheaply 

 removed from horse manure. 



Sanitary privies are absolutely necessary for the pre- 

 vention of the spread of disease by flies in country districts 

 (39). These should be required in all public places such as 

 schools, railway stations, etc., and private owners should 

 install their own in self-defense. The "wet system" should 

 be used so that the surface may be kept covered with kero- 

 sene and all possibility of fly-contamination be thus pre- 

 vented. Fly traps (see 40c) should be used on garbage 

 cans, and can be bought at most hardware stores. These 

 will catch quantities of flies and similar home-made traps 

 placed in barn windows, in barns, and wherever flies 

 assemble, will very materially aid in reducing their numbers. 



113. The Stable Fly (27).* The stable fly is so called on 

 account of its habitual presence in stables, where it becomes 

 a serious nuisance by biting cattle and horses. It closely 

 resembles the common house fly, but may be distinguished 

 by its strong mouth-parts, which enable it to make a sharp 

 "bite," and by the black spots on the abdomen (Fig. 129). 

 On this account stable flies are sometimes called "biting 

 house flies" by those who do not distinguish them, and the 

 saying has come that "flies bite before a storm," because 

 the stable flies enter houses and are more annoying just be- 

 fore a storm. The stable fly has recently come into prom- 

 * Stonwxys calcitrans Linn. Family Muscidce, see page 141. 



