90 THE STABLE FLY. 
The number of generations of this insect annually has not been 
determined, but it is estimated that seven broods may readily develop 
in one year in the Southern States. In the Northern States probably 
five broods is about the usual number. 
HIBERNATION. 
In the southern part of the United States there is no true hiber- 
nation of this insect. The adults have been found to emerge at 
various times throughout the winter, and during warm periods at 
Dallas, Tex., they have been observed to feed on animals. Mr. W. 
V. King reports that considerable numbers of adults were present 
throughout the winter of 1912-13 at New Orleans, La. In fact, they 
appeared to be even more numerous in midwinter than during the 
previous fall. At Victoria, Tex., Mr. J. D. Mitchell found them to 
annoy stock throughout the winter. Although no egg laying ap- 
peared to take place during the winter of 1912-13 at Dallas, Tex., 
it may sometimes occur at that latitude and probably occurs through- 
out the winter in the extreme southern part of the United States. 
It would seem that most of the dividuals which pass the winter 
successfully hatch from the eggs laid in the fall and continue develop- 
ment slowly during winter, emerging in early spring when conditions 
are favorable for further reproduction. Examinations of straw 
stacks in northern Texas, made during the latter part of March, 1913, 
showed a few full-grown larve and large numbers of puparia. These 
almost certainly developed from eggs deposited the previous Decem- 
ber. In the northern part of the United States it is doubtful if many 
flies emerge during the winter months, the wmter being normally 
passed in the larval and pupal stages. Near Boston, Mass., Mr. 
C. T. Brues observed adults to be active in heated stables in the dead 
of winter. These individuals probably bred out in refuse within the 
warm barns and were not hibernating adults. In 1913, at Clarksville, 
Tenn., Mr. D. C. Parman found that the adults began emerging about 
March 30. 
AGRICULTURAL PRACTICES IN RELATION TO FLY 
ABUNDANCE. 
A number of agricultural practices which are commonly in vogue 
in the United States are calculated to favor greatly the development 
of this species. As has been stated, this species breeds most com- 
monly in straw and horse manure or a mixture of these two sub- 
stances. The usual custom of allowing the manure from the horse 
stable to accumulate just outside of the stable doors absolutely 
insures the presence of a considerable number of stable flies at all 
times when climatic conditions are suitable for breeding. Allowing 
barnyards, especially around dairies, to become knee-deep in manure 
is also calculated to produce flies in abundance. 
540 
