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MISC. PUBLICATION 6 31, U. S. DEPT. OF AGRICULTURE 



4 days, and emerging as an adult in 10% days. Patton (101) 

 makes the surprising statement that, in his rearing experiments for 

 Calliphoridae in India, Sarcophaga larvae ultimately reached meat 

 kept in glass jars covered with glass lids, the edges of which had been 

 carefully coated with vaseline. 



Larva. — The larva (figs. 14 and 15) is of the usual muscoid type, the 

 anterior end usually tapering strongly from the middle toward the 

 front. The posterior end is truncate, the spiracles being located in a 

 pronounced depression or posterior cavity; above and below this 

 cavity are a number of tubercles, usually 3 on each side above and the 

 same number below, to make a total of 12. The spiracular plates lack 

 the button. Below, on the last apparent segment, is an enlarged por- 



Figure 14. — Sarcophaga crassipalpis, mature larva : A, Lateral view ; B, posterior 

 view of last body segment. 



tion, known as the anal area, which terminates on each side in a rather 

 sharp tubercle. 



No very satisfactory generic characters are known which will sepa- 

 rate this genus from Wohlfahrtia in the immature stages. The form, 

 however, is less robust in both larvae and pupae. The number of 

 branches of the anterior spiracles, given by some workers as diagnostic, 

 cannot be used, as it ranges from 4 to 20 or more. 



Descriptions of 24 first-stage larvae are given by Knipling (73) , and 

 of 4 third-stage larvae and numerous puparia by Greene (1^5). 



Pathogenesis. — The habits of different species of Sarcophaga vary 

 greatly, only a relatively small number of them being injurious to 

 human welfare. Many species parasitize grasshoppers, lepidopterous 

 larvae, and other insects and invertebrates, and a great number breed 

 in carrion. Rohdendorf (12 If) lists four classes of species of Sarco- 

 phagidae associated with man, which he designates as synanthropic 

 species as follows : (1) Species that breed in the excrement of man and 

 animals; (2) species that breed in decaying flesh; (3) species that 



