AMERICAN DIPTERA. 335 



CYRTOMA Meigen. 

 Small, finely hairy species. Antennae shorter than the head, 

 apparently two-jointed, outer joint lanceolate or ovate, with a short 

 end bristle. Proboscis short. Eyes bare, contiguous above. Thorax 

 prominent, abdomen lengthened. Legs slender, posterior pair 

 lengthened, with the tibise thickened apically ; hind metatarsi long 

 and more or less thickened. Wings with a simple third vein, no 

 discal cell, three veins arise in the middle of the wing ending in 

 the margin ; anal cell shorter than the second basal, both bounded 

 by a vein almost parallel with the hind margin ; anal angle rectangu- 

 lar, prominent. 



Hind femora incrassate, hybotine-like species, hiud tibije yellowish at base. • • -2. 

 Hind femora not incrassate, empidine-like species, legs black 3. 



2. Species measuring three millimeters, hind tibise three-fourth the length of 



their femora feiliorata Loew. 



More than four millimeters long, hind tibia? five-sixths the length of their 

 femora procera Loew. 



3. Halteres whitish, pile of abdomen dull whitish halteralis Loew. 



Halteres blackish, pile of abdomen black in part 4. 



4. Legs moderately pilose, slender and piceous loilgipes Loew. 



Legs strongly pilose, robust and jet black pilipes Loew. 



Cyrtoma Teiuorata Loew. 

 Cent. V, 69. 



Black, antennjB concolorous, third joint lanceolate. Thorax cinereo-polli- 

 nose. Pile of thorax and scutellum sparse, black. Abdomen shining, with scat- 

 tered white pile ; segments on the front half obsoletely cinereo-pollinose. Legs 

 long, black, black pilose, tips of the coxse and the knees testaceous; hind femora 

 thickened ; front tibise rather stout; hind tibiae thick, truncate, luteous, towards 

 the tip black. Halteres whitish. Wings fusco-cinereous, veins fuscous, stigma 

 obsoletely subfuscous. 3 mm. 



New Hampshire (Osten Sacken). 



C-yrtwina procera Loew. 

 Cent. V, 70. 



Black, antennae concolorous, third joint broad and ovate basally, slender api- 

 cally. Thorax lightly cinereo-pollinose, its pile black. Abdomen shining, with 

 scattered white pile. Legs long, black, black-pilose, apex of the coxa^ and the 

 knees luteous; hind femora incrassate; front tibise hardly thickened basally; 

 hind tibise thick, obliquely truncate, luteous, towards tip black. Halteres whit- 

 ish. Wings fusco-cinereous, veins fuscous, stigma obsoletely subfuscous. 4.5 mm. 



Sitka, Alaska (Kolenati). 



Cyrtoma halteraliM Loew. 

 Cent, ii, 46. 



Wholly black, somewhat shining. Pile of thorax and scutellum either wholly 



TEANS. AM. ENT. SOC, XXVIII. SEPTEMBER, 1902. 



