Household Insects. 87 



eggs hatch and the young wrigglers begin their active life in the 

 water, and then require only about seven or eight days to com- 

 plete their growth. Next they change to the curious pupa and 

 about two days later the perfect insect emerges. It requires but 

 10 to 15 days for this insect to complete its life cycle, and the short 

 time necessary for this explains the production of enormous 

 swarms of these winged pests as the season advances, specially 

 when it is remembered that each female may produce from 200 

 to 400 eggs. Mosquitoes breed, as most of us know, in compara- 

 tively still water, and in many places areas of this kind are some- 

 what limited or else can be reduced materially without much 

 trouble. In many cases the supply of mosquitoes may come from 

 a water barrel just outside the door or from near by pools. If 

 not practicable to do away with these by drainage, it is still pos- 

 sible to prevent to a large extent the production of the insects. 

 The experiments conducted by Dr. L. O. Howard, chief of the 

 Division of Entomology of the United States Department of Agri- 

 culture, have shown that kerosene applied at the rate of one 

 ounce to every 15 square feet of surface and renewed monthly 

 is a most efficient preventive of the breeding of mosquitoes, and 

 one that is practicable when the area of still water is somewhat 

 limited, as is the case in many localities. Kerosene can be ap- 

 plied to tanks or cisterns containing* drinking water without un- 

 pleasant results, provided the water is drawn through a pipe from 

 below the surface. This method is at least worthy a trial in many 

 places. Kerosene applied in like manner to pools frequented by 

 gad or horse flies has resulted in the destruction of many of these 

 annoying pests, and a trial of it is recommended. 



House Fly.- — This is one of our commonest pests (plate 5, figure 

 1) and its presence in large numbers in the home has .too often 

 been taken as a matter of course and no attempt made to mitigate 

 the trouble. We all know that the flies can be excluded from a 

 house to a great extent by the use of screens, but if the creatures 

 can be prevented largely from multiplying, the evil is stopped 

 at its source. It has been found that our common house fly 

 breeds in large numbers in horse manure and also to some extent 



