The problem of selecting the best bait for flies is an important one. In choosing a bait it should be remembered that it is largely the fermentation which renders the material attractive, and that baits are most attractive during their most active period of fermentation. As has been indicated, the kind of bait used should be governed by the species of flies the destruction of which is desired. This is most often the house fly.

A mixture of 1 part of a cheap cane molasses (blackstrap or New Orleans) and 3 parts of water is one of the most economical and effective baits for the house fly. Sugar-beet or stock molasses, which is very cheap in regions where produced, when mixed in the foregoing proportions is fairly attractive. 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 fermentation is almost equal to molasses and water as a fly bait. If it is desired to use the sirup immediately after making it, a small quantity of vinegar should be added. Honeybees are sometimes caught in large numbers with this bait. When this happens some of the other baits recommended should be used.

On dairy farms probably milk is next choice as a bait to cane-molasses solution, considering its convenience. The addition of ripe bananas or other fruit increases the attractiveness of the milk bait. The curd from milk, with one-half pound of brown sugar added for each pound, and water to make it thoroughly moist, is a very good bait and continues to be attractive for 10 days or longer if Kept moist. A mash consisting of one-half pound of bran, 1 quart of milk, 1 quart of water, 2 tablespoonfuls of brown sugar, and a yeast cake makes an attractive and lasting bait.

The foregoing baits are rendered more attractive by stirring occasionally.

BLOWFLY BAITS FOR USE AROUND MARKETS, ETC.

With the baits before mentioned 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 membranes which form the lining of the intestines of cattle or hogs are 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 around habitations or materials intended for human consumption.

At the front of and at loading docks of meat-packing establishments, where house flies are troublesome and blowflies are usually not abundant, it is best to bait the traps with one of the house-fly baits listed above. Around meat markets, where both house flies and blowflies abound, one of the combination baits given on page 13 should be employed.

BAITS FOR SCREW-WORMS AND BLOWFLIES UNDER RANGE CONDITIONS

Where rabbits or other wild animals are plentiful they make a very satisfactory bait for use on the ranges; in fact, they are rather better than any other available bait. The animal should be opened up so as to expose the intestines; and when the weather is very dry it is best to keep some water in the pan, as it adds to the attractiveness of the bait. Entrails and other animal refuse may be utilized in a similar way when they are available. In large trapping operations goats or sheep culled from the flock are cut up for bait, from 1 to 2 pounds of meat being used in each bait pan.

The main objection to the use of these meat baits is that some maggots are likely to complete their growth and escape from the bait pans. This can be largely avoided by adding nicotine sulphate to the water in the bait pan in the proportion of one teaspoonful to each gallon of water. This does not check the decomposition enough to reduce the attractiveness of the bait and practically prohibits the escape of any maggots.

As a substitute for wild animals or animal refuse when they are not available, experiments show that fairly satisfactory catches can be secured by utilizing dried "gut slime" or dried whole egg. The former is not generally on the market but can be prepared by packing houses at a moderate cost. Both of these materials are easily carried on a saddle horse, and all that is necessary is to place about one-fourth pound in the bait pan and add 1 gallon of water, after which the mixture should be stirred. The more frequently any of these baits is agitated, the greater the catch which will be secured. If the bait is kept well moistened it will continue attractive for 10 days or longer. These baits should be kept alkaline by the addition, once or twice a week, of a teaspoonful of washing or baking soda.

COMBINATION BAITS

With a number of the baits before mentioned both house flies and blowflies are captured. This is especially true with the "gut slime" and dried egg. Where both of these kinds of flies are abundant such baits are desirable. Certain other mixtures may also be utilized. A packing-house product known as blood tankage is a good fly bait when used before drying and with molasses and water. Fish scraps or meat scraps, especially with molasses and water added, will attract all kinds of flies. Overripe or fermenting fruit such as watermelon rinds or crushed bananas often gives very satisfactory results. A combination of overripe bananas with milk is much more attractive than either one used separately.