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STRUCTURE, DEVELOPMENT, AND BIONOMICS OP HOUSE-FLY. 499 



author in a valuable study of the insect fauna of human excre- 

 ment (1900), describes experiments in which he was successful 

 in rearing M. domes tica from human excrement both in the 

 form of loose faeces and in latrines. Newstead (1. c.), in 

 addition to confirming some of my observations, also found 

 the larvae in spent hops, dirty beddings from rabbits and 

 guinea-pigs, bedding from piggeries, and in the rotten flock 

 beds and straw mattresses which, I suppose, were either in, 

 or from, ashpits, and fouled with excremental products, 

 although it is not stated. He appears to have overlooked 

 some of the work of previous investigators. 



My studies of the breeding habits of M. domes tica were 

 initiated in 1905, and were continued in 1906, when a short 

 account of some of the results was published (1906). The 

 shortest time which I then obtained for the development of 

 any batch of larvae was twenty days, although, taking the 

 shortest period obtained for each developmental stage in the 

 .series of experiments, the development could have been com- 

 pleted in fifteen days under suitable conditions. In the 

 summer of 1907 I continued my experiments on a much larger 

 scale and under better circumstances, and the following are 

 the results of my experiments and outdoor observations : 



The larvae have been successfully reared in horse-manure, 

 cow-dung, fowl-dung, human excrement, both as isolated 

 faeces and in ashes containing or contaminated with excrement, 

 obtained from ashpits attached to privy middens, and such 

 as is sometimes tipped on to public tips. I found that horse- 

 manure is preferred by the female flies for oviposition to all 

 other substances, and that it is in this that the great majority 

 of larvae are reared in nature ; manure-heaps in stable yards 

 sometimes swarm with the larvae of M. domestica. It was 

 also found that the larvae will feed on paper and textile 

 fabrics, such as woollen, cotton garments, and sacking which 

 are fouled with excremental products if they are kept moist 

 and at a suitable temperature. They were also reared on 

 decaying vegetables thrown away as kitchen refuse, and on 

 such fruits as bananas, apricots, cherries, plums, and peaches, 



