17 



Flies breed in house-refuse, manure, or any decaying matter. They increase with 

 such rapidity that, assuming one-half of one fly's output of eggs to hatch out, live, and 

 raise families of their own, the number of flies from this single source would be 216,000 

 in thirty days, and in forty days it could amount to over 2,000,000. 



(Fie. 9.) 



The House-fly, with larva and pupa ; all highly magnified. 



Larva. 



This stage lasts about six days. 



Pupa. 

 This stage lasts about throe days. 



If a house is infested with flies, the source of the trouble is usually near at hand ; 

 for generally they do not fly a greater distance than 200 yards from their breeding-places, 

 though a high wind may carry them much farther. 



Coal-oil they abhor. It is wise, therefore, to wash over windows and round the 

 frames with coal-oil at intervals during the summer, and a good dressing of turpentine 

 round every crevice of the windows in the early spring will often destroy .flies which 

 have spent their winter in these haunts. 



It is worth while, also, to wipe over the network of the larder daily in summer 

 with coal-oil ; and saucers containing one spoonful of formalin to six of water should 

 be placed about wherever flies are seen to congregate. They are attracted to the 

 fluid and killed. 



