102 PRINCIPAL HOUSEHOLD INSECTS. 



spot wliere another cheese or food in some other form is at hand. It 

 is in this way, as well as by the more readily understood means, that 

 new cheese becomes infested and that the insect makes its appearance 

 in pantries supposed to be perfectly clean. 



REMEDIES AND PREVENTIVE MEASURES. 



When we consider the great liardihood and extreme tenacity of life 

 of this insect in the Hypopus condition, and the fact that almost every 

 flying or crawling thing may become its common carrier, the difficulty 

 of disinfecting a storeroom and of keeping it disinfected becomes very 

 plain. Nothing, in fact, but the utmost cleanliness and watchfulness 

 will prevent the appearance of the mites. When they have once entered 

 a cheese, for example, there is no remedy except to cut out the infested 

 portions. All energies must be bent toward i)revention. If a given 

 room seems to be badly infested it should be cleaned out, fumigated 

 with sulphur, and washed out thoroughly with kerosene emulsion. 

 Food supplies liable to be infested should be inspected daily during 

 hot weather. 



It is a point of considerable interest and of some practical account 

 that there often occur, where these mites are present in numbers, one or 

 more species of predaceous mites which feed exclusively on the injurious 

 individuals and tend to greatly lessen their numbers. Some years ago 

 a gentleman in Milwaukee sent the writer some thousands of mites 

 which were found in a bin of wheat in an old elevator. They occurred 

 in such numbers that every morning a quart or more could be swept 

 up below the spout where they had sifted out. An examination of 

 specimens sent showed that three species of predaceous mites were 

 present among the others, and one of them was so numerous that there 

 was no hesitation in writing to the Milwaukee gentleman that the pre- 

 daceous mites would probably soon destroy the wheat feeders and thus 

 the pest of mites would correct itself. The prediction was speedily 

 verified in part a week or so later, when the correspondent wrote: "As 

 you say, the parasitic mites have largely destroyed the smaller ones, 

 and I suppose when their food is all gone they will die of starvation.'' 



THE CHEESE SKIPPER OR HAM SKIPPER. 



(Piophila casei Linn.) 



A small, glistening, black, two-winged fly lays its eggs on cheese, 

 smoked ham, and chipped beef. The eggs liatch into small white cylin- 

 drical maggots which feed upon the cheese or meat and rapidly reach 

 full growth, at which time they are one-fifth of an inch in length. The 

 maggot is commonly called •' skipi^er" from its wonderful leaping pow- 

 ers, which it possesses in common with certain other fly larvae, all of 

 which are devoid of legs. The leap is made by bringing the two ends 

 of the body together and suddenly releasing them like a spring. In 

 this way it will sometimes jumj) 3 or 4 inches. 



