THE STABLE FLY. 27 
DESTRUCTION OF IMMATURE STAGES AND PREVENTION OF BREEDING. 
Since straw stacks have been found to be the principal breeding 
places of this insect in the grain belt, the proper care of the straw is 
by far the most important step in control. The straw should be 
stacked more carefully than is ordinarily done, when it is desired to_ 
keep it for protection and food for live stock. This may be accom- 
plished by making the sides of the stack nearly vertical and rounding 
it up well on top, in order the better to shed the rain. 
So far as possible, all straw which is not required for winter feed for 
stock should be disposed of immediately by burning, or by scattering 
it over the land soon after thrashing and subsequently plowing it 
under, or by burning the stacks. The plowing under of the straw is 
the most advisable method of procedure, as by this practice large 
amounts of humus are added to the soil. Oat straw is most generally 
used for feeding purposes, and it is this straw which forms the principal 
Fic. 10.—Pile of flies caught in a Hodge flytrap. (After Hodge.) 
breeding ground for flies. It is therefore important that all of the oat 
straw needed for feed or bedding be baled and stored under cover 
and that the remainder be promptly burned or scattered. 
All straw stacks not consumed by stock during the winter should 
be promptly disposed of in the early spring, as these stacks furnish 
flies continuously during spring and summer. Often the flies reared 
in such situations are abundant enough to cause great annoyance to 
live stock during early spring, and by multiplying throughout the 
summer an almost incredible number of flies are produced by fall. An 
examination of an oat-straw stack at Gainesville, Tex., in March, 1913, 
showed a very large number of pup, from many of which flies were 
emerging. In portions of this stack it was estimated that 300 pup 
were present in each cubic foot of straw. This illustrates the im- 
portance of disposing, in spring, of straw which has been carried over 
the winter. Disposition of the stacks in spring may be accomplished 
in the same way as has been suggested to be followed in the fall. 
The conditions which produced the unusual outbreak in 1912, that 
is, the heavy rainfall on the freshly thrashed straw, rendered the straw 
540 
