DAIRY INSPECTION 165 
with a spray pump or syringe, is an effective and safe repellent. 
The following mixture, it is claimed, will act effectively for one 
week: Soap, 1 pound; water, 4 gallons; crude petroleum, 1 
gallon, and powdered naphthalene, 4 ounces. The soap is shaved 
into thin slices and dissolved in the water by heating; the 
naphthalene is dissolved in the crude oil. The two solu- 
tions are mixed by stirring vigorously or churning for 15 
minutes. The mixture is stirred thoroughly each time before 
using and is applied to the cows with a brush once or twice 
weekly. While fly repellents afford the cow temporary relief 
from the biting flies, they are of no value in the control or 
eradication of the flies. Hellebore and borax have not been 
tested on the larve of the cow-fly, but it is very probable that 
they would be as destructive to these larve as to those of the 
house-fly. 
When cows are kept in the stable, with occasional liberty 
in an exercise yard, the breeding of cow-flies can be prevented 
by removing the manure from the stable and yard to the fields 
daily, or if it is stored in the vicinity of the stable, by removing 
it to the fields at intervals of not less than 12 days, provided 
the floor of the stable and the floor of the dung-stead are so 
constructed that the pupz cannot burrow into the ground. 
When cows are pastured it is not practicable to control the 
breeding of cow-flies. The manure dropped in the pasture fur- 
nishes ideal breeding conditions. When the flies emerge they 
take up a position on the body of the cow, where they feed and 
rest, and are carried into the stable by the cow. 
The stable-fly breeds in horse manure and in decaying grass 
and straw heaps; also in cow droppings which have become dry 
and disintegrated, and in ensilage. Eggs deposited in these 
substances hatch out larve in 1 to 3 days. The larve develop 
into pupz in 11 to 30 days or more, and the flies emerge in 
6 to 20 days, the time from the egg to the fly being 18 to 53 
days and upwards. The stable-fly feeds on the blood of cows 
and other domestic animals, and also bites man. Unlike the 
house-fly, it is not likely to infect milk with bacteria, since it 
does not feed upon that substance. 
