180 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.48. 



bearing long but scattered hairs on the lower half; some specimens 

 have a few hairs upon the upper portion of eyes ; in one specimen eyes 

 almost nude. 



Thorax and scutellum opaque cinereous pollinose, two pairs of 

 longitudinal vittas visible, inner pair narrow, distinct anterior to suture, 

 obsolete posterior thereto. Outer vittas reduced to mere spots. 

 Post-sutural macrochaetas three, sterno-pleural bristles usually four. 

 Scutellum bearing three pairs of marginals, the apical pair being 

 longest. Abdomen ovate, cinereous pollinose with a slightly brassy 

 shine. A weak median macrochaeta, or sometimes two, distinguish- 

 able on margin of second abdominal segment. Legs, including tarsi, 

 entirely black. Wings hyaline. Veins yellowish, first posterior cell 

 either distinctly open or barely closed in costa close to but before the 

 wing tip. The angle of the posterior cross vein measures 115°, the 

 average of 10 specimens, male and female. Length, 6-8 mm. De- 

 scribed from six specimens. The male differs from female in that he 

 is shining black excepting the front, base of second and all of third 

 and fourth abdominal segments, which are cinereous pollinose. 



WEBSTERIANA, new genus. 

 Plate 6, fig. 4. 



Palpi present well developed, antennae reaching only slightly below 

 middle of the face, first longitudinal vein bare, costal spine long, 

 costa with a narrow but distinct break at tip of auxiliary vein. Sides 

 of face bearing a row of frve or six slender proclinate macrochaetas 

 extending from base of antennas to near lower corner of eye. First 

 posterior cell closed, petiolate ending well before tip of wing. Hind 

 cross vein at middle of discal cell or slightly before. Cheeks less than 

 one-half eye height, lower occiput swollen. Head nearly as long at 

 vibrissas as at base of antennas, eyes of male distinctly hairy, in female 

 bearing indistinct scattered hairs. Vibrissas situated about the 

 length of second antennal joint above oral margin. 



Type of the genus. — Tricogena costalis Coquillett. 



This genus is named in honor of Prof. F. M. Webster. Mr. Coquil- 

 lett's specimen was a unique female in bad state of preservation. My 

 series of 10 specimens, including both sexes, shows conclusively that 

 it can not be placed in Tricogena Rondani. It is distinct from Me- 

 tachseta by its b are first vein and from RhinopJiora by the row of mac- 

 rochaetas on cheeks, bare arista, etc. 



WEBSTERIANA COSTALIS Coquillett. 



Plate 6, fig. 5. 



Slender, black, silvery pollinose, wings milky, costal margin infus- 

 cated. Length 5 mm. Front in female at narrowest part same width 

 as eye, in male one-half as wide. Two pairs of orbitals in the female, 

 absent in male. Entire head exclusive of frontal vitta hoary frosted 



