FLYTRAPS AND THEIR OPERATION. ll 
it can be procured without charge and in others it is sold at from 
5 to 10 cents per gallon. On dairy farms, probably milk is the next 
best bait, considering its convenience. The tests indicate that milk 
is not more than one-third as effective as beer and rather less so than 
a mixture of cheap molasses and water. This mixture is prepared 
by adding 3 parts of water to 1 part of “ black-strap ” molasses and 
allowing it to ferment for a day or two. All baits, milk, beer, etc., 
are much more attractive during active fermentation. Sirup made 
by dissolving 1 part of ordinary brown sugar in 4 parts of water 
and allowing the mixture to stand a day or two to induce fermen- 
tation is almost equal to the molasses and water as a fly bait. If 
it is desirable to use the sirup immediately after making it, a small 
amount of vinegar should be added. Honey bees are sometimes 
caught in large numbers at this bait. When this happens some of 
the other baits recommended should be used. In the experiments it 
ras found possible to secure catches equal to those obtained by using 
stale beer through the employment of homemade malt extract; this 
is slightly troublesome to make and therefore does not recommend 
itself for general use except in towns and cities where flytraps are 
being operated by individuals who give much time to this work. 
This extract is prepared by using 1 gallon of water to 2 pounds of 
ground malt. The latter may.be purchased at about $1 per bushel 
and ground in a coffee mill. The water is heated to 135° F., the 
malt added, and then during a:period of 45 minutes the temperature 
is gradually raised to 160° F. The extract is then strained off the 
grain, cooled, and is ready for use. 
With the baits before mentioned comparatively few blowflies will 
be caught. For use about slaughterhouses, butcher shops, and other 
places where blowflies are troublesome, it has been determined that 
the mucous membrane from the lining of the intestines of hogs is 
without equal as a bait. This material, which is commonly spoken 
of as “gut slime,” can be obtained from packing houses where 
sausage casings are prepared. The offensive odor of this bait renders 
its use undesirable near materials intended for human consumption. 
Another packing-house product known as blood tankage is a good fly 
bait when used with beer. This combination results in the capture 
of a large percentage of house flies. Still better results are obtain- 
able by using “ gut slime” in combination with beer. Where these 
materials are not obtainable fairly good catches will result from the 
use of fish scraps or meat scraps. With any of these baits the catches 
will be found not to be entirely meat-infesting flies, as actual counts 
have shown that the precentage of house flies in traps over such baits 
ranges from 45 to 75. 
Overripe or fermenting fruit, such as bananas, crushed and placed 
in the bait pans sometimes gives satisfactory results. A combina- 
