No. 2301. NEW SPECIES OF MUSCOID FLIES— TOWNSEND. 559 



present. Parafacialia narrow, bare. Cheeks about one-fourth eye 

 length. Two sternopleurals and preacrostichals ; thi'ee postintraalars, 

 postsuturals, postacrostichals, and lateral scutellars; a weak apical 

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

 cell widely open a little before tip. Hind crossvein a little nearer to 

 cubitus. Male claws short. All four abdominal segments with 

 marginal row. 



LYDELLOTHELAIRA COLLARIS. new species. 



Length, 7.5 mm.; of wing, 8 mm. One male, Casahuiri, Peru, 

 4,500 feet, February 4, 1910 (C. H. T. Townsend). 



Brown to blackish. Parafacialia and most of parafrontalia pale yel- 

 lowish pollinose; clypeus and facialia thinly silvery. Antennae 

 blackish; first two joints brov/n. Frontalia light brown. Palpi 

 brown. Thorax and scutellum soft dark brown; mesoscutal suture 

 bordered in front by a narrow irregular silvery fascia confluent with 

 silvery of humeri, and extending obliquely and broadly down on 

 pleura. Abdomen subshining brown; last three segments with nar- 

 row anterior border of silvery to pale brassy pollen. Wings nearly 

 clear. Tegulae whitish, narrowly edged with yellow. 



Type.— C&t. No. 22219, U.S.N.M. 



THELAIROCHAETONA, new genus. 



Genotype. — TJielairocJiaetona thrix, new species. 



Clypeus moderately sunken. Epistoma cut off; faintly warped. 

 Facialia bare. Proboscis very short; palpi stout and bowed. Third 

 antennal joint about four times second. Arista longer than antennae, 

 thin, finely pubescent one-fourth way. Eyes bare. Female vertex 

 one-fourth head width. Two frontals below base of antennae. Two 

 strong proclinate fronto-orbitals in female. Ocellars present. Para- 

 facialia narrow, bare. Cheeks hardly one-fifth eye length. Three 

 sternopleurals, postintraalars, postsuturals, preacrostichals and lat- 

 eral scutellars; two postacrostichals; short apical pair of scutellars. 

 Costal spine present. First vein bristled nearly halfway; third 

 bristled to small crossvein; others bare (one bristlet on fifth vein in 

 one wing). Apical cell widely open considerably before tip. Hind 

 crossvein nearer to cubitus. Median marginal pair on first two seg- 

 ments ; median discal pair on second and third ; marginal row on last 

 two; and discal row on anal segment. 



THELAIROCHAETOMA THRIX, new species. 



Length, 9 mm. One female, Porto Bello, Panama, April 18, 1912 

 (A. Btisck). 



Blackish, cinereous pollinose. Palpi rufous. Pollen of parafronta- 

 lia with strong golden tinge. Antennae blackish. Frontalia soft 



