6 THE STABLE FLY. 
tropical, and temperate regions in which domestic animals are reared, 
especially where those animals are kept in considerable numbers, the 
fly is a pest of importance. The absence of severe cold in the winters 
and the moist warm conditions prevailing in many of the countries 
bordering on the Tropics allow almost continual breeding; hence in 
these regions the fly is of importance throughout the entire year. 
The stable fly has been in the United States for many years. 
Although it is probable that it was introduced from Europe with live 
stock brought here by the earliest colonists, we have no definite 
knowledge regarding its first occurrence in this country. The strong 
flight of the fly and its close association with domestic animals has 
permitted it to spread to all parts of the country. 
The abundance of the species appears to be dependent largely upon 
local and seasonal conditions. In the southern part of the United 
States the insect is a pest of more or less importance throughout the 
year, but is usually most abundant in the latter part of the summer 
and during the fall. In the North and West it seldom becomes suf- 
ficiently numerous to cause annoyance to stock until the latter part 
of the summer and the early fall, the injury diminishing rapidly after 
heavy frosts. It appears that the fly is of much more importance as 
a pest in the grain belt than elsewhere. This point will be discussed 
more fully in another part of the paper. 
From time to time climatic and other conditions have been favor- 
able for the production of flies in great numbers, but little definite 
information is at hand regarding severe outbreaks which occurred 
prior to 1912. Old residents in the north-central part of Texas state 
that exceedingly large numbers of flies were present during the sum- 
mer of 1867. Another outbreak occurred in parts of Texas in 1894 
or 1895, and in 1905 the flies were again numerous enough to cause 
serious loss. 
Notes have been published from time to time, in early entomological 
papers, on the injuriousness of this insect. In September, 1888, we 
find in Insect Life a reference to it as a pest to horses in Oregon. 
The correspondent in this case stated that the fly made its appear- 
ance at Salem, Oreg., two or three years before, though this informa- 
tion can scarcely be considered as reliable. This same issue of Insect 
Life also includes the statement that in the spring of 1888 the fly 
was reported to have caused considerable annoyance to cattle in 
Maryland and New Jersey. 
In Kansas and Nebraska it has been determined that it is a pest of 
some importance every year throughout the grain belt of those 
States, but occasionally it appears in much greater numbers than 
normal. Statements made by farmers in other sections of the 
country where grain is grown extensively, notably in the Dakotas 
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