THE STABLE FLY. mA 
In the grain belt it is the general practice for farmers to thrash the 
grain in the fields by means of self-stacking thrashing machines. 
The individual stacks cover much ground and the straw is very loosely 
piled. In many cases for convenience a large number of stacks are 
formed in various parts of a field. This condition, when followed 
by more or less heavy summer and fall rains, is certain to produce 
great numbers of flies. In fact, this is precisely the condition which 
occurred in 1905 and in 1912, when the serious outbreaks of the fly 
occurred in Texas. In many instances straw stacks are not protected 
from live stock. The animals soon scatter the straw about and by 
adding manure to the straw still further favor the breeding of flies. 
These straw stacks are usually allowed to remain from one year to 
the next without any attention whatever. When the succeeding 
crop is planted the area occupied by the stacks is simply left uncul- 
tivated. In a number of instances 50,000 square feet have been 
found occupied by a single stack, and in many cases several of these 
stacks occurred in a field of 60 or more acres. <A railroad official 
recently computed that the area covered by wheat stacks in Kansas 
alone is no less than one-fourth of a million acres. Such stacks are 
usually allowed to remain throughout the fall and winter and in a 
few cases are burned the following spring. More frequently, how- 
ever, they are left from year to year and the new straw added to the 
old stacks, destruction only taking place when the stacks become 
exceedingly large. It will be seen that these practices not only 
encourage the breeding of the stable fly, but when the straw becomes 
sufficiently rotten and compact the house fly as well breeds in it in 
abundance. Throughout the grain belt a very considerable amount 
of valuable land is untilled and the full manurial value of the straw 
is lost. Of course the stacks serve some purpose as shelter and food 
for live stock kept in the fields during winter. In fact, this is the 
only legitimate reason for not scattermg them or burning them in 
the late summer or fall. 
NATURAL CONTROL. 
CLIMATIC EFFECT. 
The adults feed when the temperature is very high and the sun 
bright and hot as well as durmg cool and cloudy weather. They 
have also been observed to attack animals during drizzling rain, and 
when somewhat protected by sheds and stables they often feed during 
heavy rain. The lowest temperature at which flies have been 
observed to partake of blood was 55° F. When the temperature 
goes below 60° F. their desire to feed is less marked. Between 40° 
and 48° F. they lose their ability to fly, and complete inactivity occurs 
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