THE STABLE FLY. 7 
and Minnesota, indicate that the fly is sufficiently numerous nearly 
every year to cause considerable trouble. In the Southwestern 
States it sometimes becomes very abundant, although records of 
serious outbreaks have not been made. In central and southern 
Louisiana it is often very annoying to all live stock. This is especially 
true in the region where rice is grown extensively. It appears from 
investigations conducted in the central part of Florida that the 
stable fly is seldom present in sufficient numbers to attract attention. 
Prof. C. P. Gillette, of the Colorado Agricultural College, says in a 
recent letter, ‘‘Possibly the common stable fly is really the worst 
pest [of live stock in Colorado] on account of its being so abundant 
and ever present.’’? In northern Colorado and southern Wyoming, 
at altitudes of from 5,000 to 7,500 feet, the writer has observed the 
insect to annoy horses and cattle greatly during the latter part of 
summer. From a statement made by Prof. J. M. Aldrich we learn 
that it is troublesome to cattle in Idaho, and Prof. R. W. Doane 
states that it is one of the worst fly pests to live stock in California. 
THE SEVERE OUTBREAK OF THE STABLE FLY IN 1912. 
During the late summer and early fall of 1912 an unprecedented 
outbreak of this pest occurred in northern Texas. The area of 
greatest abundance was practically coextensive with regions where 
grain was extensively produced that season. The most severe 
injury was experienced in Grayson, Cook, Collin, and Denton Counties, 
in northern Texas. The fly was also abundant as far south as Hill 
County and as far west as Wichita County, and in parts of southern 
Oklahoma it also caused much alarm. In certain parts of Kansas 
and Nebraska it was also said to be more abundant than normal. 
In Texas the flies appear to have become seriously numerous about 
August 12 and the outbreak to have continued in its severe form 
until the end of August. Fles were, however, very numerous 
throughout September and the greater part of October, but rapidly 
diminished after cold weather began. Under a number of the suc- 
ceeding topics reference is made to conditions which prevailed during 
this outbreak. Some of these illustrate the severity of the pest 
during such an occurrence. 
A study of the conditions existing in northern Texas during 1912 
showed that the flies were breeding to a great extent in straw stacks. 
Unusually heavy rains occurred in the early part of August, and as 
most of the straw was freshly threshed and had not become settled, 
the rain deeply penetrated the stacks. The straw became heated 
immediately and formed very attractive breeding places for flies. 
The grain crop of 1912 was one of the largest ever produced in Texas, 
and as the straw was also heavy a great number of straw stacks 
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