REPORT OF THE STATE ENTOMOLOGIST 1908 25 
various species, although annoying and under certain condi- 
tions dangerous, sink into insignificance compared with the common 
house fly. 
Habits. The house fly subsists entirely upon fluids taken up by 
means of the fleshy tongue. It apparently feeds with equal gusto 
upon fresh manure, decaying vegetable matter or the daintiest 
culinary preparations. This catholicity of taste frequently results 
in flies feeding greedily upon exposed discharges, in open vessels 
or poorly constructed privies, from patients suffering from 
tvphoid fever or other grave intestinal diseases. The hairy legs 
are thus fouled with thousands of deadly bacilli and countless 
numbers of germs are swallowed. Shortly thereafter the same 
flies may appear in the house and incidentally contaminate the food, 
to the great peril of the consumer, with the germs adhering to the 
limbs and those deposited with undiminished virulence in the 
familiar fly specks. This, while disgusting and abhorrent to every 
sense of decency, occurs repeatedly in nature and is apparently 
ignored by the masses, despite the deadly peril incurred. 
There is abundant evidence to show that this insect breeds by 
preference in horse manure, though it also occurs to a limited 
extent in cow manure and in miscellaneous collections of filth and 
specially decaying vegetable matter. The parent insects deposit 
their eggs upon manure and similar materials, the young maggots 
hatching therefrom in less than 24 hours and, under favorable 
conditions, completing their growth in five to seven days later. 
The maggots then transform to the oval, brown, resting or pupal 
stage, remaining therein from five to seven days. The life cycle 
is thus completed in to to 14 days, the shorter period being true 
of the warmer parts of the year, particularly in the vicinity of 
Washington, D. C. One fly may deposit about 120 eggs, and as 
there may be 10 to 12 generations in one season, it is not surprising 
that this insect should become extremely abundant by midsummer. 
Calculations show that under favorable conditions the descendants 
from one fly might at the end of a season reach the stupendous 
number of over 190 quintillion. Dr Howard’s studies show that 
as many as 1200 house flies, in various stages, might be found in 
‘one pound of manure. At this rate, one good load of manure 
tight produce two and a half million flies. Fortunately, breeding 
is confined to the warm months, only a few flies wintering in houses 
in a more or less dormant condition. 
