SOUTH AMERICAN DIPTERA. 285 



teuuse are inserted is luteous yellow. Face in profile vertical, and straight from 

 the root of the antennje to the oral margin, obtusely keeled, on either side with 

 a patch of silvery gray dust. Front opaque on the upper part, yellowish dusted 

 across the middle. Mesonotum opaque, an intra-humeral, and a slender, inter- 

 rupted sutural band, yellow poUiuose. Scutellum thinned at the tip, and with 

 eight or ten small, but distinct, spinous bristles on its margin. Abdomen opaque ; 

 first segment, lateral margins of the second, anterior angles of the third, and the 

 fourth wholly, moderately shining greenish metallic. Hind femora moderately 

 thickened, with numerous spines below, and a patch of short silvery pile in front 

 toward the base; hind coxae with a small, acute, spinous tubercle. Wings tinged 

 with brownish, more strongly distally in front, the stigma elongate brown ; third 

 vein gently curved backward. 



One specimen, Rio de Janeiro. 



S4. Syritta aniericana Schiner. 



Three male and one female specimens from Rio de Janeiro and 

 Chapada are ])robably this, but the males differ from the description 

 in having a broad, narrowly interrupted, yellow abdominal hand; 

 the first three joints of the four_ anterior, not the hind, tarsi are very 

 light yellow, and the marginal cell of the wings from beyond the 

 auxiliary vein is filled out with dee]) brown. The known variations 

 in tS. pipiens are such that I would not consider these differences 

 (Schiner may have overlooked the brown marginal cell) specific, 

 without further proof. The feniale differs in having no yellow on 

 the abdomen, the opaque second and third segments showing shining 

 metallic places to correspond to them ; my single female also has a 

 shining black spot above the oral margin. The third antennal joint 

 is fully twice as long as the first two together. 



85. Sterphiis ceer alius Eondaui (Xylota). 

 S. antennalis Philippi. 



I will notice here a specimen of this species kindly sent me by 

 Mr. Roeder, who called my attention to the above synonymy, which 

 I can corroborate. The male hind coxae have a long slender spur 

 beneath. The specimen is from Chili. 



CERIOGASTER gen. nov. 



Allied to Xylota, the fece carhiate and the abdomen much con- 

 tracted on the basal segments. Head flattened ; face short, in pro- 

 file gently convex. First two joints of the antennae short, third 

 elongate oval. Eyes bare, subcontiguous in the male, in the female 

 the front narrowed above. Antennae inserted near the middle of the 



