344 THE POPULAR SCIENCE MONTHLY. 



Dr. Packard kept a fly in a bottle from 6 p. M. one day until 

 8 A. m. the following day, in which time one hundred and twenty 

 eggs were laid. 



Oftentimes flies are found dead on the window-sills or adher- 

 ing to the walls or ceilings, a white powder surrounding them ; 

 death in these cases having been caused by a parasitic plant grow- 

 ing upon them, the white powder observed about them being the 

 spores of the plant. 



It is, perhaps, hardly necessary to speak of the various meth- 

 ods 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 be- 

 ing used. 



Mosquito (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 penny- 

 royal (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 



