64 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 83 



length of second segment; arista brown, thickened as usual and 

 tapering toward tip, penultimate segment long; face yellow, silvery 

 pollinose, the lower border prominent and its ridges flat and bare; 

 cheeks silvery pollinose on yellow ground color, bearing three or 

 four moderately large bristles at middle, about three-fourths the 

 eye height; proboscis rather long and slender, apical segment taper- 

 ing toward tip, with a small labella ; palpi absent ; beard w hite. 



Thorax black, gray pollinose, with four narrow black dorsal 

 stripes, the outer ones interrupted at suture; pleura clothed with 

 black hairs ; scutellum dusted with gray pollen, apex red. Chaeto- 

 taxy: Acrostichal, 3, 3; dorsocentral, 3, 3; humeral, 5; posthumeral, 

 2; notopleural, 2; presutural, 2; intraalar, 3; supraalar, 3; postalar, 

 3; petropleural, 2 (large); sternopleural, 2, 1; scutellum with 3 

 lateral, 1 small decussate suberect aj^ical, and a discal pair situated 

 behind the middle; postscutellum normal, gray pollinose; calypters 

 opaque, white. 



Abdomen black, subshining, with thin changeable gray pollen on 

 three basal segments, sides of the intermediate ones tinged with 

 red; anal segment wholly red, covered with dense whitish pollen 

 to tip ; first segment without median marginal bristles ; second with 

 one stout pair; third with a still larger pair and four at the side; 

 fourth with a strongly arcuate row of about 10 discals, behind these 

 a siibmarginal and a marginal row of smaller bristles; no discals 

 on intermediate segments; genitalia reddish with a large paler 

 lateral lobe; inner forceps united on entire length and bowed for- 

 ward, convex at base behind, the surface punctate clothed with fine 

 hairs, tapering beyond middle to a narrow blunt apex ; outer forceps 

 bowed backward near base and directed inward when viewed from 

 the rear, shining black on apical half; fifth sternite with a broad 

 U-shaped incision, the lobes reddish, lightly sprinkled with pollen 

 and sparsely black haired. 



Legs black, tibiae reddish; front claws and pulvilli shorter than 

 apical tarsal segment; mid tibia with two stout bristles on outer 

 front side near base ; hind tibia with a row of about five wide-spaced 

 uneven bristles on outer posterior side. 



Wings gray-hyaline; third vein with bristly hairs extending 

 almost to small cross vein; last section of fifth vein distinctly less 

 than half the length of preceding section ; fourth vein with a rounded 

 rectangular stumpless bend ; the apical cross vein undulates slightly 

 and gradually narrows the first posterior cell which is open far 

 before the tip of wing; costal spine vestigial; epaulets red. 



Female. — Front at vertex 0.434 of the head width in the one speci- 

 men ; orbital bristles two or three proclinate and one divergent re- 

 clinate pair situated slightly before the uppermost frontal outside 



