No. 2301. NEW SPECIES OF MUSCOID FLIES— TOWNSEND. 565 



Arista faintly pubescent one-third way. Eyes thinly short-haired. 

 Male vertex about one-seventh head width. Two frontals below 

 base of antennae. No proclinate fronto-orbitals in male. No 

 ocellars. Parafacialia very narrow, bare. Cheeks about one-eighth 

 eye length. Two sternopleurals and postsuturals ; three postintra- 

 alars, preacrostichals, postacrostichals, and lateral scutellars; very 

 weak apical scutellar pair. Costal spine strong. Tliird vein bristled 

 only at base; others bare. Apical cell narrowly open just before tip. 

 Hind crossvein nearer to cubitus. Male hind tibiae strongly bowed, 

 claws long. Median marginal pair on first two segments and marginal 

 row on last two. 



TELOTHYRIOSOMA TERSA, new species. 



Length, 7.5 mm. One male, Cayuga, Guatemala, April, 1915 

 (William Schaus) . 



Palpi fulvous. Antennae wholl}^ clear pale fulvo-rufous, including 

 base of arista. Face thinly silvery; front brassy. Thorax and 

 scutellum brassy with four dark vittae; inner pair narrow and linear. 

 First two abdominal segments clear light yellow; narrow median 

 vitta and last two segments, including posterior edge of second, 

 largely due to dried contents of abdomen, brown; third segment 

 thinly brassy, showing most on front edge; anal segment thickly 

 brassy. Legs brown. Wings and tegulae moderately smoky. 



Type.— Csit. No. 22234, U.S.N.M. 



MICROCHAETONA, new genus. 



Genotype. — Michrochaetona gracilis, new species. 



Differs from PhyllopMlopsis as follows : Very slender. Only two 

 sternopleurals and postintraalars. One strong vertical in male. 

 Male abdomen not very much longer than thorax, in shape like the 

 female of PhyllopMlopsis. Male wings only about twice as long as 

 thorax. 



MICROCHAETONA GRACILIS, new species. 



Length, 3 to 3.5 mm. Two males, Yahuarmayo, Rio Inambari, 

 Peru, 1,700 feet, February 12, 1910, on fohage (C.^H. T. Townsend). 



Dark brown to blackish. Frontalia with golden reflection in 

 oblique view. Palpi pale yellowish to fuscous. Antennae blackish. 

 Rest of head silvery. Thorax, scutellum, and abdomen shining 

 brown ; humeri and median vitta in front of suture silvery. Pleura 

 faintly silvery. Legs pale brown, tarsi darker. Wings light smoky- 

 yellow, pale on inner border and axilla. Tegulae glassy-fuscous. 



Type.— Cat. No. 22236, U.S.N.M. 



OPSOLESKIA, new genus. 



Genotype. — OpsolesMajlava, new species. 



Clypeus appreciably sunken. Epistoma wide, short, faintly 

 warped. Facialia bare. Proboscis little over half head height; palpi 



