4 BULLETIN 1453, U. S. DEPARTMENT OF AGRICULTURE 



DISTRIBUTION 



In common with many other domestic species, the cheese skipper has 

 become widely distributed through commerce. There are records 

 of its occurrence in nearly all countries of continental Europe, in 

 England, India, the West Indies, Greenland, Alaska, and many lo- 

 calities in this country. In its capacity as a scavenger it is capable 

 of perpetuating itself in carrion, and this is an excellent reason for 

 believing that it has become established in many other parts of the 

 world. 



The records of cheese-skipper damage in the files of the Federal 

 Bureau of Entomology include the District of Columbia and localities 

 in the following States : Alabama, California. Illinois, Maryland, 

 Massachusetts, New York, North Carolina, Pennsylvania, Tennessee, 

 and Virginia. Melander and Spuler have specimens from Idaho, 

 Kansas, Louisana, South Dakota, Texas, and -Washington. 



MATERIALS INFESTED 



It was generally believed that the older, softer, and richer cheeses 

 were most subject to attack, the accuracy of which opinion is evident 

 from laboratory experiments in which the infestation of old dry 

 cheese was observed to be a slow process. In the time of Redi (168S) 

 (58) the epicures boasted that they knew how to grow worms in 

 cheese to please the palate. Swammerdam (73, p. 63) stated that 

 the worms were " generally held in detestation, though some eat them 

 voluptuously with the rest of the cheese, from a vulgar notion, that 

 they are formed out of the best parts of it * * *." Linne (4#, 

 p. 456) gave the habitat of this species as cheese; Scopoli (69) de- 

 fined its food as soft, buttery, moist cheese; whereas Fabricius (21, 

 p. 780) listed w * dunghills, cheese and other fats/' 



The first mention of attacks on ham and bacon appeared, as already 

 noted, in 1806. Bouche (13, p. 99) stated that the larva? are found in 

 human excrement, in the summer and fall; rotten fungus was given 

 as a host food by Zetterstedt (83, p. 2510) . John Curtis (16 < p. 126) 

 received larvae from powdered rhubarb, and Germar (26) was given 

 a sample of cooking salt infested with the larva?, both occurrences 

 probably being explainable by larval migration to these substances 

 for pupation. 



The occurrence of cheese-skipper larva? in human cadavers was 

 first recorded by Rondani (65, p. 21fi) in 1874. Large numbers of the 

 larva? were found infesting an exposed human cadaA^er at Paris in 

 December. 1888. the account of which forms a part of Megnin's treat- 

 ise (47, p. 170) on the significance of the insect fauna of corpses in 

 determining the date of death. The point in the entomological se- 

 quence in such cases chosen by Piophila. he stated, is that at which 

 decomposition has reached the stage where fatty acids and caseous 

 products are present, or from the third to the sixth month. 



The findings of Megnin were criticized and compared with their 

 own observations by Johnston and Villeneuve (36). These investi- 

 gators reported the examination of exposed cadavers in Canada, one 

 in May and one in August, infested with the cheese skipper, which, 

 they concluded, appears only after the saponification of the fat i* 

 well marked. 



