SOME INSECTS AFFECTING CHEESE, HAMS, FKUI'J', ETC. 103 



This insect, like so many other househohl species, is cosmopolitan, 

 and was doubtless originally imi)orte(l from Europe into the United 

 States. 



Careful o])servations on the life history of this species have been 

 made by several writers. In 1892 3Iiss M. E. Murtfeldt. whose atten- 

 tion was called to the species on account of the great damage Avhich it 

 was represented to be doing in certai:! Western packing and curing 

 establishments, studied the life history of the summer generation.^ 

 The eggs were showji by Miss Murtfeldt to be deposited in more or less 

 compact clusters of from 5 to 15, and also scattered singly. In her 

 observation jars the average number was 30 to a single female, but it is 

 possible that under these abnormal conditi(jns the number was smaller 



YlG. iS.—Pioj)hila casei: o, larva; fc, pnparinm: <•, pupa; rf, male fly ; c, female -with wings folded — all 



enlarged (original). 



than usual. The egg; is white, slender, oblong, slightly curved, 1 mm. 

 in length, with a diameter of about one-fourth its length. Hatching 

 takes i)lace within thirty-six hours. The larva is cylindrical, tapering 

 gradually toward anterior end, and truncate posteriorly, furnished at 

 liinder extremity with two hornj- projecting stigmata and a pair of 

 fleshy filaments. The larva completes its growth in from seven to eight 

 days, attaining a length of from 7 to 9 mm. While feeding, if the food 

 supply is sufficient it does not move about much, entire clusters of 

 larvae often comjdeting their growth in the same crevice in which the 

 mother flies deposited their eggs. When mature, however, it moves 

 away to some dry spot, contracts in length, assumes a yellowisli color, 

 and gradually forms into a golden-brown pui)ariuni 4 or,") mm. in length. 



' Insect Lile, ^'ol. VI, pp. 170-175. 



