G5 
the inaiiure resulted in decided relief from house Hies in the neij^libor- 
ing- house. Where it is imssibk', tlieii, to build such ii receptacle, tiiis 
course is advised. 
All stables should be kept scrui)ul()usly clean. The stable of the 
Department of Agriculture, in which observations had been made, is 
kei)t very clean and probably very few Hies breed there. It is swept out 
and washed out frecjuently. The horse drop])ings are removed care- 
fully each twenty-four hours and placed in a pile beside the stable, 
whence, at intervals of a week or more, they are removed to the com,- 
post heap some distance away. The daily pile attracts hosts of flies 
and is soon swarming with larvie. 
In order to ascertain the numbers in which house-fly larva'> occur in 
horse-manure piles, Mr. Busck,at the request of the writer (and, by the 
way, Mr. Busck has assisted in all of the experiments), took a quarter 
of a pound of rather well-infested horse manure on August 9, and 
counted in it IGO larva', and 146 puparia. This would make about 1,200 
house flies to a pound of manure. This, however, can not be taken as an 
average, as no larva? are found in, perhaps, the greater i)art of the ordi- 
nary manure pile. Neither, however, does it show the limit of what can 
be found, since Mr. Busck counted about 200 i)upie in less than one cubic 
inch of manure taken from a si^ot 2 inches below the surface of the pile 
where the larvje had congregated in immense numbers. 
There are no other horse stables in the immediate vicinity of the 
Department of Agriculture, and it is reasonable to suppose that the 
treatment of this temporary pile every third or fourth day by spraying 
it with kerosene, i^ouring on water and turning it with a fork, will have 
an appreciable effect on the number of house flies which, during every 
summer, annoy the ofldcials of the Department. This treatment should 
be begun early in the season, since, as with other insects, it is immensely 
more efl'ective to kill a single individual in the spring than at a later 
season of the year. This is plainly shown from an estimate which the 
writer has made, to the eftect that from a single overwintering female 
house fly there may be descended in the course of the following 
summer a number of individuals mounting into the sextillions. For the 
person who is curious about statistics of that sort it would be interest- 
ing to estimate the length of a line of flies of this number, or the weight 
of this number of flies, and so on. 
It seems to the writer that many persons may consider it worth while 
to go to the slight trouble needed to treat manure piles in this way and 
to keep their stables clean. Not only the house fly but the biting 
stable fly (Stomoxys calcitrans) will be killed in this way, and the writer 
is nor at all sure, in view of the possibilities in the way of transmis- 
sion of disease by both the house fly and the stable fly, that it would 
not be advisable for city boards of health to pass regulations insisting 
upon greater cleanliness of stables and such a treatment of manure as 
has been described. 
11930— No, 10 5 
