36 MISC. PUBLICATION 631, U. S. DEPT. OF AGRICULTURE 



The arista is very short-haired and may appear bare under lower 

 magnifications ; the eyes are broadly separated in both sexes, more so 

 in the female than in the male; vein r x is bare. 



A taxonomic treatment of the species of the world has been made by 

 Salem {129). Of the 17 known, 3 are of medical importance; the 

 others, as far as known; being scavengers or parasitic on insects. 



Larva. — Too little is known of the immature stages of the Sarco- 

 phagidae to make possible any positive statement of generic characters. 

 In the known species of Wohlfahrtia, the branches of the anterior 

 spiracles are few in number, usually 5 to 9, rarely 10, and spread out 

 fanlike ; most species of Sarcophaga have the branches more numerous, 

 but this is not universally true. The more robust form of the 

 Wohlfahrtia larva will aid in distinguishing it from Sarcophaga. 



As in Sarcophaga larvae, the anterior end tapers strongly from the 

 middle toward the front; however, the general form is much more 

 robust. The posterior end is truncated, the spiracles being located in a 

 pronounced depression or posterior cavity ; above and below this cavity 

 are 12 tubercles, 3 on each side above and the same below; these 

 tubercles are less strongly developed than in Sarcophaga (fig. 9). 

 Below, on the posterior face of the last apparent segment, is an en- 

 larged portion known as the anal area, which, as in Sarcophaga, 

 terminates on each side in a prominent tubercle. Prominent spinous 

 areas are present at either the anterior or posterior margins of the 

 segments, or both. 



Extensive descriptions and figures of larvae in the various stages are 

 given by Portchinsky (US) for Wohlfahrtia magnifica and by Walker 

 (168) for W. vigil. 



Pathogenesis. — Two entirely different types of myiasis are pro- 

 duced by members of this genus. In Eurasia, W. magnifica produces 

 a serious form of traumatic and rhinal myiasis, whereas in the northern 

 United States and Canada W. vigil and W. opaca produce a f uruncular 

 subcutaneous type in children. 



KEY TO SPECIES 



1. Abdomen chiefly shining black, with isolated pollinose areas in 4 



longitudinal rows, 2 down the middle of the segments and 1 on each 



side vigil (Walker) 



Abdomen chiefly pollinose, with 3 longitudinal rows of shining black 

 spots 2 



2. The central spot on the third segment large and usually triangular, pro- 



longed forward to touch, or nearly so, the base of the central one on 



the second segment ( 3 



The central spot on the third segment smaller ; in the female it is limited 

 to the apical part of the segment; in the male it is flasklike, the body 

 being small and the neck prolonged forward naba (Wiedemann) 



3. Second antennal segment orange-colored and approximately equal in 



length to the third; palpi orange opaca (Coquillett) 



Second antennal segment black and distinctly shorter than the third ; 

 palpi black magnifica (Schiner) 



WOHLFAHRTIA MAGNIFICA (Schiner) 



(Fig. 10) 



Synonyms. — Sarcophila magnifica Schiner; Sarcophaga magnifica (Schiner); 

 Sarcophila wohlfahrti Portchinsky. 



Recognition Characters. — Adult: The antennae are black, at most the apex 

 of the second segment being yellowish or reddish ; the third segment is half again 

 to twice as long as the second. The palpi are black. There are about four 



