44 CYRTIDAE OF NORTH AMERICA 



as in some of the other genera. The callosities of the thorax are 

 not very large and the seutellum is rather small and short, as in 

 Acrocera. The squamae are noticeably smaller in proportion 

 than in most of the genera, and are not bulging as in Ogcodes and 

 Acrocera. The halteres are of medium size. 



Abdomen large, appearing more square than conical in outline, 

 with short fine pile. The legs are quite slender. Discal cell 

 long and narrow, the proximal end pointed. Cross-veins rather 

 far from wing margin, so that the posterior cells are long. The 

 wing veins are strong and reach the wing margin. The third 

 vein is branched; four posterior cells, the first is separated from 

 the outer first basal by a remarkable cross-vein. Anal cell closed 

 in some, widely open in others. Anal angle of wing much re- 

 duced. One species, pterodontinus, has a large tooth on the 

 costa, as in the genus Pterodontia; this tooth is heavier, however, 

 and nearer the proximal end of the wing than in that genus. 



Synopsis of Species 



1. Wing with costal spur as in genus Pterodontia pterodontinus O. S. 



Wing with costa thickened, but without a spur 2 



2. Anal cell closed; third posterior cell about as long as fourth 3 



Anal cell open; third posterior cell shorter than fourth 4 



3. Wings brownish .... gagatinus Loew 



Wings tinged slightly with brownish, the base and apex subhyaline, metallic 



grayish brown body color diligens O. S. 



4. The sixth vein prolonged to wing margin sulphuripes Loew 



The sixth vein interrupted long before the wing margin paucus O. S. 



Opsehius formosus Loew (Provence), 0. pepo Loew (Spain) an,d 

 0. inflatus Loew (Europe) have the body black and yellow, and 

 not uniformly blackish as in the American species. 



Opsebius gagatinus 



Opsehius gagatinus Loew, Centuries, vi, p. 24. 



"Blackish, shining, legs and halteres reddish yellow, wings fuscous-black, 

 first posterior cell divided by a cross-vein. Length, 2| lines. Wing, 3 V12 

 lines. 



"Blackish, shining, head and thorax with rather long subfuscous hair, hair of 

 abdomen shorter and paler. Coxae black, legs all yellowish red. Tegulae 

 medium, dirty yellow red, pale pilose, the margins fuscous. Halteres pale 

 lutescent. Wings entirely fuscous black, veins black and disposed as in 0. 

 inflatus, however anterior cross-vein is oblique, and the other adjacent cross- 

 vein, which divides the first posterior cell, is between the end of the discal 

 and the base of the second submarginal cell." 



