54 THE HOUSE FLY—DISEASE CARRIER 
traordinary flight of the gadflies of the family Taban- 
idse, which for hours will circle about the horses, fly¬ 
ing with ease much more rapidly than the speed of the 
vehicle, alighting only occasionally. It is not intended 
to convey by these instances the impression that it is 
known that the house fly is at all extraordinary as a 
flier among the Diptera—in fact, when the truth is 
fully known it may be shown to be comparatively a 
weak flier among its relatives; but it darts here and 
there through the air with great speed, and if it were 
obliged to fly great distances the writer has little doubt 
of its ability to do so. 
The practical question involved in the distance of 
flight, however, is the one of protection of food sup¬ 
plies at a distance from fly breeding places which can¬ 
not be controlled. Will the proper care of the stables 
and houses in a given city square relieve the houses in 
this square from the fly pest to a measurable degree, 
provided stables and houses one square or two squares 
away remain uncared for? The situation must be 
much as it is with mosquitoes, although the house fly 
is a much stronger flier than any mosquito. The house 
fly will seldom travel very much farther than it has to 
fly for food and a proper nidus for its eggs, but as a 
matter of fact it is very difficult to prove this. Fur¬ 
ther experimental work should be carried on in this di¬ 
rection. 
J. S. Hine {in lit.) states that in the summer of 1910 
he made an effort to determine the distance that flies 
travel. At a barn where he was carrying on some work 
