BREEDING HABITS 91 



Theobald has reported the breeding of flit's on refuse tips. 

 In India Surgeon-Major Smith has also found that horse-manure 

 is the commonest breeding place of M. doitiestica, especially 

 around the military camps. He has also reared it from cow- 

 dung. 



Orton (1910), in some investigations quoted by Howard (1911), 

 found house-fly larvae in a mixture of horse and cow-manure 

 underneath a farm bam, and it is interesting to note that the 

 larvae and puparia were more abundant in that portion of the 

 pile where the horse-manure was either pure or predominated. 

 Pupae were also found in piles of pig-manure mixed with straw 

 bedding exposed to the air and rain. An ounce of this material 

 taken fi-om a point a few inches below the surface showed 868 

 pupae. Flies were also found breeding in spent hops and brewery 

 waste (malt) ; an ounce of the latter contained 1018 maggots. In 

 an experiment one pound of material constituting these breeding 

 places was taken and kept in screen-covered glass jars in the 

 laboratory for ten days. The following was the result: 



As How^ard points out, these results were no doubt in the 

 main correct, although the identification of the flies was by no 

 means thorough, as Orton admits. 



During the summers of 1908 and 1909 Prof. S. A. Forbes, 

 State Entomologist of Illinois, U.S.A., had observations carried 

 out in Urbana, 111., by Mr A. A. Girault, and in Chicago by 

 Mr J. J. Davis, on the breeding habits of the house-fly with 

 a view to discovering what substances, other than the usual 

 breeding place, horse-manure, served as breeding places. The 

 results of these observations have been published by Howard 

 (1911) and are as follows: 



