STRUCTURE, DEVELOPMENT, AND BIONOMICS OF HOUSE-FLY. 4.99 
author in a valuable study of the insect fauna of human excre- 
ment (1900), describes experiments in which he was successful 
in rearing M. domestica from human excrement both in the 
form of loose feces and in latrines. Newstead (l.c.), in 
addition to confirming some of my observations, also found 
the laryvee 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. domestica 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 larvee 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 larvee have been successfully reared in horse-manure, 
cow-dung, fowl-dung, human excrement, both as isolated 
feeces 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 larvee are reared in nature ; manure-heaps in stable yards 
sometimes swarm with the larve of M. domestica. It was 
also found that the larvee 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, 
