No. 2301. NEW SPECIES OF MUSCOID FLIES— TOWN SEND. 563 



Shining dark brown. Frontalia with fulvo-cupreous reflection in 

 oblique view. Face, third antennal joint and sides of front silvery. 

 Palpi fuscous. Thorax silvery; with three wide black vittae; the 

 middle one more or less fulvous pollinose on median line before suture 

 especially in male; the outer ones interrupted by a narrow silvery 

 pollinose border on hind edge of prescutum. Scutellum and abdomen 

 without pollen except the narrow thinly silvery bases of last three 

 segments. Wings and tegulae moderately yellowish-fuscous; paler in 

 female. 



Type.—Qsii. No. 22230, U.S.N.M. 



URODEXIA SIAMENSIS, new species. 



Length, 13 mm. to end of tail; tail, 5 mm. One male, Khow Sai 

 Dow, 1,000 feet, Trong, Lower Siam, January to February, 1899 

 (W. L. Abbott). 



Head silvery, shading to golden on sides of front. Palpi fuscous. 

 Antennae black; third joint grayish. Frontalia dark brown. Pleura 

 silvery; mesoscutum golden, with four narrow dark brown vittae; the 

 outer ones widely interrupted at suture and abbreviated anteriorly, 

 while behind suture they are connected by a broad dark brown fascia 

 covering a little more than the anterior half of the postscutum. 

 Scutellum dark brown except the golden tip, as though crossed by a 

 similar dark fascia. Abdomen brown; the bases of intermediate seg- 

 ments broadly golden poUinose; anal segment silvery with the tail 

 brown. Legs light brown. Wings and tegulae lightly smoky-yellow. 



Type.— Ca^t. No. 22267, U.S.N.M. 



PSEUDOCHAETONA, new genus. 



Genotype. — PseudocJiaeiona polita., new species. 



Head characters of Pseudodexia. Third antennal joint four or five 

 times second. Arista longer than antennae, slender, thinly short- 

 plumose to tip. Eyes bare. Frontals one or two weak below base 

 of antennae. One vertical in male. Ocellars vestigial. Para- 

 facialia very narrow, bare. Cheeks hardly one-eighth eye length. 

 One preacrostichal, postacrostichal and lateral scutellar; two 

 sternopleurals and postintraalars ; three postsuturals ; long decussate 

 apical scutellar pair. Third vein bristled only at base; others bare. 

 Apical cell open just before tip. Hind crossvein nearly in middle. 

 Apical crossvein deeply bowed in. No median marginals on first 

 segment, but a pair on second; marginal row on last two segments. 



PSEUDOCHAETONA POLITA, new species. 



Length, 6.5 mm. One female, Trinidad Rio, Panama, March 25, 

 1912 (A. Busck); one male, Yahuarmayo, Peru, February 10, 1910 

 (C. H. T. Townsend). 



