

AMERICAN MUSEUM GUIDE LEAFLETS 
The cone (K) is cut from the screen and either sewed with fine wire 
or soldered where the edges meet at (L). The apex of the cone is 
then cut off to give an aperture (M) 1 inch in diameter. It is then 
inserted in the trap and closely tacked to the hoop around the base.”’ 
The effectiveness of the traps will depend on the selection of 
a good bait. For attracting house flies beer is probably the best. 
It loses much of its attractiveness after the first stages of fermentation 
are over, and for this reason it should be renewed every day or two. 
Milk is also a good bait. Over-ripe or fermenting bananas, crushed 
and placed in the bait pans, give good results. A combination of 
bananas and milk is more attractive than either used separately. A 
mixture of 3 parts water and 1 part cheap molasses is very attrac- 
tive after it has been allowed to ferment for a day ortwo. A mixture 
of equal parts of brown sugar and cheese (or curd of sour milk), 
thoroughly moistened, give good results after it has been allowed to 
stand for three or four days. For catching blow flies and other meat- 
infesting flies, the best bait is the mucous membrane from the lining 
of the intestines of hogs. Ordinary fish or meat scraps may be used. 
Fly paper is sometimes helpful, particularly the long slender 
roll of sticky paper hung froma ceiling. Fora fly poison, Professor 
Phelps of the United States Public Health Service recommends either 
formaldehyde or sodium salicylate, three teaspoonfuls of the 40 per 
cent. commercial solution of formaldehyde, or the same amount of 
powdered sodium salicylate to a pint of water. Nearly fill a glass 
tumbler with the solution, place over this a piece of blotting paper 
cut to circular form and somewhat larger in diameter than the tum- 
bler, and over this invert a saucer. Invert the whole device. The 
blotting paper will remain in the proper moist condition until the 
entire contents of the tumbler have been used and the strength of the 
formaldehyde solution will be maintained. A little sugar sprinkled 
upon the paper will increase the attractiveness of the poison for the 
flies. Either of these preparations may be safely used where there 
are young children, although the addition of the sugar is not recom- 
mended in such cases. 
The killing of flies in the house by ‘“‘swatters’’ is also of some 
value, although where the insects are abundant the majority of them 
should be eliminated by the more efficient methods of trapping. 
Among natural enemies which help to destroy flies in either the 
larval or the adult state are hens, swallows, phoebes and other birds, 
and toads. 
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