3 
become more abundant of later years. It breeds in the dust under 
carpets, and its larva is a white, very slender, almost thread-like creature. 
In the autumn, when fruit appears on the sideboard, many specimens 
of a small fruit-fly (Drosophila ampelophila Loew) (fig. 7) make their 
appearance, attracted by the odor of 
overripe fruit. 
A small, slender fly is not infrequently 
seen in houses, especially upon window 
panes. This is Sepsis violacea Meig., 
shown enlarged in figure 8. 
All of these species, however, are 
greatly dwarfed in numbers by the com- 
mon house fly. In 1900 the writer made 
collections of the flies in dining rooms 
in different parts of the country, and out 
of a total of 28,087 flies 22,808 were 
Musca do- 
: Fig. 3.—Muscina  stabulans, enlarged 
mestica ; (author’s illustration). 
that is,98.8 
per cent of the whole number captured. 
The remainder, consisting of 1.2 per cent 
of the whole, comprised various species, 
including those mentioned above. 
LIFE HISTORY OF THE TRUE HOUSE FLY. 
Musca domestica commonly lays its eggs 
upon horse manure. This substance seems 
to be its favorite larval food. It will ovi- 
Fie. 4.—Phormia terreenove, enlarged posit on 
(author’s illustration). 
cow ma- 
nure, but we have not been able to rear 
it in this substance. It will also breed 
in human excrement, and from this 
habit it becomes very dangerous to the 
health of human beings, carrying, as 
it does, the germs of intestinal dis- 
eases such as typhoid fever and cholera 
from excreta to food supplies. It will 
also lay its eggs upon other decaying 
vegetable and animal material, but of 
the flies that infest dwelling houses, 
5 Ree Fic. 5.—Lueilia cesar, enlarged (author’s 
both in cities and on farms, a vast illustration). 
proportion comes from horse manure. 
At Salem, Mass., Packard states that he bred a generation in four- 
teen days in horse manure, The duration of the egg state was twenty- 
