Page:Popular Science Monthly Volume 37.djvu/358

344 Dr. Packard kept a fly in a bottle from 6 one day until 8  the following day, in which time one hundred and twenty eggs were laid.

Oftentimes flies are found dead on the window-sills or adhering to the walls or ceilings, a white powder surrounding them; death in these cases having been caused by a parasitic plant growing upon them, the white powder observed about them being the spores of the plant.

It is, perhaps, hardly necessary to speak of the various methods of preventing the entrance into our houses of these annoying insects, or the manner of expelling when, in spite of screens and nettings, we find them in our rooms. One must be always on the watch, and better than any fly-trap or fly-paper is the little whisk broom, constantly at hand to be used on these disturbers of the peace. A strong solution of quassia, mixed with sugar to attract the flies, is said to be an excellent fly-poison.

Flies can be kept out of stables by keeping the floor well swept and clean, and sprinkled with kerosene-oil, only a very little being used.

(Cidex pipiens).—Another dipterous insect which frequents our dwellings is the common mosquito, an insect too well known to need any description. During the season a female will lay about three hundred eggs in several litters. These eggs are deposited in standing water, running water being free from them on account of the danger of the mosquito being drowned when emerging from its pupa-case, which serves as a sort of raft until the wings and legs are strong enough to support the perfect insect.

The egg hatches soon after being deposited, and the young lives upon decaying matter, growing very rapidly and changing its skin several times. While in the pupa, state it takes no food, and, unless disturbed, remains near the surface of the water. In about four weeks after hatching, the pupa-skin splits along the back, and the mosquito appears. It is perhaps hardly necessary to mention that it is only the female that bites, or, more properly speaking, stings.

A writer in Nature says that the "smell of American pennyroyal (Hedeoma pidegioides), when sufficiently strong, drives them away at once." This remedy is often given, but I have never yet seen it used with any effect. Another writer in the same journal advises the use of a solution made by pouring boiling water upon quassia-chips. This wash may be applied and left to dry on the skin, acting as a preventive against the annoyances of mosquitoes, gnats, etc. In a later volume of Nature a writer reports having tried this wash with no beneficial results; still, it may be of use in some cases, and, being so simple, could easily be