358 NORTH AMERICAN DIPTERA 



Family Diopsidae — The Stalk-eyed Flies 



Sphyrocephala brevicornis Say. 



The members of this family are mostly rather small, with the eyes 

 situated on the ends of long stalks, a character not developed in onr 

 one genus. 



Weakly haired, almost bare, the head transverse, sliort, conspicu- 

 ously produced toward either side so that the eyes are separated by 

 about four times their width; antenna very widely separated, the basal 

 segments short, the third roundish, with dorsal arista; front bare except 

 at the vertex; oral vibrissas absent. Legs of moderate length, the 

 anterior femora thickened and with short spines beneath. Auxiliary 

 vein closely approximated to the first vein for most of its length but 

 ending far before it; second basal cell united with the discal cell; apical 

 cell somewhat narrowed apically; anal cell long, the anal vein short. 



The only American representative of this family is Sphjiracephala 

 hrevicomis Say, a quite small and inconspicuous species. In tht- 

 Nearctic region there are no flies which resemble it in the shape of its 

 head but in the Neotropical region there are many Otitida- and 

 Drosophilidae which have the eyes more or less stalked, one Otitid 

 having much longer stalks than any true Diopsid I have seen. 



Our single species is found along the edges of streams, ponds and 

 marshy lakes and occurs from early si)ring to late autumn and has been 

 taken in numbers about a privy and on skunk-cabbage. The immature 

 stages are unknown. 



This family has a particular fascination for most peo|)le owing 

 to the peculiar structure of the head. Why the eyes are stalked we do 

 not know and there may be no reason for it. 



