AMERICAN DIPTERA. 335 



€YRTOMA Meigen. 

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

 apparently two-jointed, outer joint lanceolaJ;e or ovate, with a short 

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

 prominent, abdomen lengthened. Legs slender, posterior pair 

 lengthened, with the tibiae 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, hybotiue-Iike species, hind tibiae yellowish at base. . . -2. 

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



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



their femora feiuorata Loew. 



More than four millimeters long, hind tibiae 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 lougipeiji Loew. 



Legs strongly pilose, robust and jet black pilipes Loew. 



Cyrtoiua feinorata Loew. 

 Cent. V, 69. 



Black, antennae concolorous, third joint lanceolate. Thorax cinereo-poUi- 

 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 coxae and the knees testaceous; hind femora 

 thickened ; front tibiae 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'yrtoma 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 coxw and the 

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

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

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



Sitka, Alaska (Kolenati). 



Cyrtoina halteralis Loew. 

 Cent, ii, 46. 



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



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



