4 
which the Bureau of Entomology is situated. This stable has always 
been very carefully kept. The manure was thoroughly swept up every 
morning, carried outside of the stable, and deposited in a pile behind 
the building. This pile, after accumulating for a week or ten days, or 
sometimes two weeks, was carried off by the gardeners and spread 
upon distant portions of the grounds. At all times in the summer this 
manure pile swarmed with the maggots of the house fly. It is safe to 
say that on an average many thousands of perfect flies issued from it 
every day, and that at least a large share of the flies which constantly 
bothered the employees in the two buildings mentioned came from this 
source. 
On the basis of the experiments of 1897, an attempt was made, 
beginning early in April, 1898, to prevent the breeding of house flies 
about the Department by the treatment of this manure pile with kero- 
sene. The attempt was begun early in April and was carried on for 
some weeks. While undoubtedly hundreds of thousands of flies were 
destroyed in the course of this work, it was found by the end of May 
that it was far from perfect, since if used at an economical rate the kero- 
sene could not be made to penetrate throughout the whole pile of’ 
manure, even when copiously washed down with water. <A considerable 
proportion of house-fly larvee escaped injury from this treatment, which 
at the same time was found, even at an economical cost, to be laborious, 
and such a measure, in fact, as almost no one could be induced to prac- 
tically adopt. 
There remained, however, another measure which had been suggested 
by the writer in an article on the house fly published in 1895, namely, 
the preparation of an especial receptacle for the manure, and this was 
very readily accomplished. A closet 6 by 8 feet had been built in the 
corner of the stable nearest the manure pile. It had a door opening into 
the stable proper, and also a window. A door was built in the outside 
wall of this closet, and the stablemen were directed to place no more 
manure outside the building; in other words, to abolish the outside 
manure pile, and in the future to throw all of the manure collected each 
morning into this closet, the window of which in the meantime had 
been furnished with a wire screen. The preparations were completed 
by the middle of June, and a barrel of chlorid of lime was put in the 
corner of the closet. Since that time every morning the manure of the 
stable is thrown into the closet, and a small shovelful of chlorid of 
lime is scattered over it. At the expiration of ten days or two weeks 
the gardeners open the outside door, shovel the manure into a cart, and 
carry it off to be thrown upon the grounds. 
Judging from actual examination of the manure pile, the measure is 
eminently successful. Very few flies are breeding in the product of the 
stable which formerly gave birth to many thousands daily. After this 
measure had been carried on for two weeks, employees of the Depart- 
