232 Fiftieth REroRT ox the State Museum 



as do their larvae, commonly known as " skippers," from their habit of 

 bringing the two ends of the body together and by sudden straightening 

 with a quick muscular action throwing themselves to a distance of four 

 or five inches or more. The larva or skipper "is cylindrical, tapering 

 gradually toward the anterior end, truncate posteriorly, and furnished at 

 this extremity with two horny projecting stigmata and a pair of fleshy 

 filaments (see a in the figure). The egg is pearly white, slender oblong, 

 slightly curved, i mm. in length, with a diameter of about one-fourth the 

 length " (Murtfeldt). 



Life-History. 



For our knowledge of the life-history of tlie insect, we are mainly 

 indebted to the careful observations of Miss Murtfeldt. 



The eggs are deposited in more or less compact clusters of five to 

 fifteen in the cracks and checks of cheese, upon the surface of cured or 

 partially cured meats, and, in the case of canvassed meats, on the cover- 

 ing or in its folds ; sometimes they are scattered singly. The number of 

 eggs deposited averaged about thirty in the breeding cages, though the 

 conditions were not normal and the number may have been diminished 

 in consequence. A popular article in Harper's Neiv Monthly Magazine 

 {loc. at.) credits this insect with depositing nearly three hundred eggs, 

 which is probably a gross over-estimate. 



The eggs hatch within thirty-six hours, and the tiny white maggots attack 

 at once their food — in meat, the fatty portions. They complete their 

 growth in seven to eight days and are then seven to nine millimeters 

 (about one-third of an inch) in length. The transformation from the 

 full-grown larva to the perfect fly occupies ten days. In the breeding 

 cage, adult flies on an average did not live longer than a week. They 

 would sip a little at sweets but were not greatly attracted to them, while 

 the odor of smoked meats speedily drew them. The flies were not 

 active at night, although they could perform their functions in partially 

 darkened places. No definite succession of generations could be noted, 

 but the insect in all stages was present from May until into October or 

 November. Severe and protracted cold proved fatal to the insect in all 

 its stages. The above is the result of Miss Murtfeldt's observations on 

 the insect in the month of August and later. 



In February of the same year. Prof. Kellogg, then of the Kansas State 

 University, studied the development of this insect. According to his 

 observations, the egg stage lasted four days; the larvae required two 

 weeks to complete their growth, and they remained in the pupa state one 

 week. Dr. H. F. Kessler, as quoted by Dr. Howard, has carefully studied 

 the life-history of this fly in Europe. He found that the average time 



