10 HOUSE FLIES. 
Nor are the disease-bearing possibilities of the house fly limited to 
intestinal germ diseases. There is strong circumstantial evidence 
that tuberculosis, anthrax, yaws, ophthalmia, smallpox, tropical 
sore, and parasitic worms may be and are so carried. Actual labo- 
ratory proof exists in the cases of a number of these diseases, and 
where lacking is replaced by circumstantial evidence amounting 
almost to certainty. 
REMEDIES AND PREVENTIVES. 
A careful screening of windows and doors during the summer 
months, with the supplementary use of sticky fly papers, is a pre- 
ventive measure against house flies known to everyone, and there 
seems to be little hope in the near future of much relief by doing away 
with the breeding places. A single stable in which a horse is kept 
will supply house flies for an extended neighborhood. People living 
Fig. 7.—The fruit fly (Drosophila ampelophila): a, Adult; b, antenna of same; c, base of tibia and 
first tarsal joint of same; d, puparium, side view; ¢, puparium from above; /, full-grown larva; 
g, anal spiracles of same. Allenlarged. (Author’s illustration.) 
in agricultural communities will probably never be rid of the pest, 
but in cities, with better methods of disposal of garbage and with the 
lessening of the number of horses and horse stables consequent upon 
‘electric street railways, bicycles, and automobiles, the time may come, 
and before very long, when.window screens may be discarded. The 
prompt gathering of horse manure, which may be variously treated 
or kept in a specially prepared receptacle, would greatly abate the 
fly nuisance, and city ordinances compelling horse owners to follow 
some such course are desirable. Absolute cleanliness, even under 
existing circumstances, will always result in a diminution of the num- 
bers of the house fly, and, in fact, most household insects are less 
attracted to the premises of what is known as the old-fashioned house- 
keeper than to those of the other kind. 
459 
