HOUSE FLIES. bE} 
NATURAL ENEMIES. 
The house fly has a number of natural enemies. The common 
house centipede (fig. 13) destroys it in considerable numbers; there 
is a small reddish mite which fre- 
quently covers its body and gradu- 
ally destroys it; it is subject to 
the attacks of hymenopterous para- 
sites in its larval and pupal condi- 
tion; and it is destroyed by preda- 
tory beetles at the same time. 
The most effective enemy of the 
house fly, however, is a fungous 
disease known as L’mpusa muscae, 
which carries off flies in large 
numbers, particularly toward the 
close of the season. The epidemic 
ceases in December, and, although 
many thousands are killed by it. 
the remarkable rapidity of de- 
velopment in the early summer 
months soon more than replaces 
the numbers thus destroyed. 
PREVENTIVE AND CONTROL 
- MEASURES. 
THE USE OF SCREENS. 
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. As regards 
screening it is only necessary here 
to emphasize the importance of 
keeping food supplies screened or 
otherwise covered so that flies can 
gain no access to them. This ap- 
ples not only to homes, but also to 
stores, restaurants, milk shops, and 
as 
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Fic. 13.—The house centipede (Scutigera 
forceps) : Adult, natural size. (After 
Mailatt.) 
the hike. Screening will, of course, have no effect in decreasing the 
number of flies, but at least it has the virtue of lessening the danger 
of contamination of food. 
