420 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



jnacrochaetae only marginal. Abdomen of male much narrower 

 than that of female. 



Closely similar to Minthopsis vittata in both structure and color, 

 and evidently related to that genus, but generally more slender in 

 form and legs much more elongate, besides the following characters: 

 Second aristal joint of female barely twice as long as wide, that of male 

 fully three times as long as wide. Front of male about width of one 

 eye, that of female about one and one-fifth times eye-width. Male 

 frontalia wider than those of female. Male parafrontals narrower 

 than those of female; male parafacial plane practically parallel with 

 the longitudino-vertical plane of head. Eyes very thinly short-hairy 

 in both sexes, shghtly more so in male, bare below in female. Vibrissae 

 inserted well above oral margin in both sexes; the facial plate very 

 elongate and nearly equilateral. In front view the male facialia- 

 crests are quite in Hne with inner border of eyes. Faciaha ciHate to 

 well above niiddle in both sexes, more strongly so in male. Face 

 and front nearly equal in width, former shghtly wider, latter shghtly 

 narrowed at vertex. Prochnate oceUar bristles present. Eyes 

 dscending as low as vibrissae in male, well short of same in female. 

 Cheeks of female about one-third eye-height, those of male about 

 one-fourth same. Frontal bristles descending to base of third 

 antennal joint. Three sternopleural and three postsutural bristles. 

 No decussate scutellar bristles, the long pair in middle divaricate. 

 Abdominal segments one to three in both sexes with a median mar- 

 ginal pair of macrochaetae, and one or two lateral marginal; bristles 

 of anal segment marginal only. Claws of both sexes short, practically 

 alike. Legs long, metatarsi very long; front tarsi of female not 

 noticeably swollen or modified. Apical cell open close to wingtip. 

 Only two or three bristles at base of third vein. Hind crossvein 

 decidedly nearer to cubitus in both sexes. 



RHOMBOTHYRIOPS ELEGANS, new species. 



Length of body, 5 to 6.5 mm.; of wing, same measurements. Two 

 females and ten males, Huariaca, Peru, high montanya of the Rio 

 Huallaga Canyon, about 10,750 feet, on fohage, December 20, 1913 

 (Townsend) . 



Pale golden pollinose, with wholly velvet-black antennae and 

 arista, broad velvet-black frontaha, two velvet-black mesoscutal 

 vittae of same width as frontaha, narrow blackish border to scutel- 

 lum, and four broad velvet-black fasciae on abdomen occupying the 

 hind half or so of the four segments. Cheeks and occiput paler, more 

 silvery. Palpi fulvous, faintly smoky on tips. Male parafrontals 

 invaded by the black from frontaha. Male scutellum prevaihng 

 black; mesoscutal vittae appearing confluent behind suture in male 

 in certain hghts. Postscutellum wholly golden. The abdominal 



