SMfTHSONIAN INSTfTUTION LIBRARIES 



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since it shows so plainly that care and cleanliness coml)ine(l with such 

 an arrangement as that described will in an individual stable measur- 

 ably affect the fly nuisance in neighboring buildings. 



With the combined efforts of the persons owning stables in a given 

 comnumity, nuich more effective results can undoubtedly be gained. 



We iire accustomed to think of the house fly simply as a nuisance, 

 but they are undoul)tedly the carriers of the germs of typhoid fever, 

 breeding in and frequently visiting uncovered uncared-for human 

 excreta. The enforcement, therefore, of cleanliness in stables and 

 the obligatory building of receptacles for horse manure, woidd seem 

 to the writer subjects worthy the consideration of the boards of health 

 of our cities. 



The house fly has a number of natural enemies, and the common 



4iouse centipede destroys it in considerable numbers; there is a small 



reddish mite which frequently covers its body and gradually destroys 



it; it is subject to the attacks of hymenopterous parasites in its larval 



condition, and it is destroyed by predatory l)eetles at the same time. 



The most effective enemy, however, is a fungus disease known as 

 Empmuui /)iiisca\ which carries off' flies in large numbers, particu- 

 larly toward the close of the season. The epidemic ceases in Decem- 

 l)er, and although many thousands are killed by it, the remarkable 

 rapidity of development in the early sunnner months soon more than 

 replaces the thousands thus destroyed. 



L. O. Howard, 



Entomologist. 



Apjiroved : 



Ja:mes Wilson, 



Secretary. 



Washingtox, D. C, Jidy 11, 1808. 



[Cir. 35] 



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