{February 1885, BULLETIN BROOKLYN ENTOM. SOC. VOL. VII. 187 
EF, —Thinly ee hind tibize in the male with an internal, median spur 
Teuchocnemis, O. S. 
HE.—Third joint of the antennee ovate; thorax usually with distinct stripes: 
eyes of male broadly separated...........-...-.- Helophilus Meig. 
. SERICOMYINAE. 
Large species; antennz short, the third joint scarcely longer than 
broad; arista basal, plumose; anterior cross-vein of wings oblique, near 
the middle of discal cell; hind femora sometimes thickened. 
_A.-—Moderately pilose; abdomen with yellow interrupted cross—bands, third longitu- 
dinal vein never considerably curved..............0..+5. Sericomyia, Meig. 
AA.—Thickly pilose, abdomen uniformly black; third longitudinal vein considerably 
CUTVCC ee ARIE te he diame ela iS De Pane a Peale Arctophila, Schiner. 
XYLOTINAE. 
Anterior cross-vein near or beyond the middle of the discal cell; 
arista dorsal, bare; third longitudinal vein only gently curved, marginal 
cell open; thorax without yellow markings other than sometimes on the 
humeri. 
A.—Long, slender, abdomen narrowed toward the base (Baccha). 
AA.—Abdomen never linear or club shaped. 
B.—Nearly bare species, especially on the abdomen, the pile never long or dense; 
eyes bare. 
C.—Face strongly carinate; hind femora thickened, with an angular protuber— 
ancespelow neartherend: .. . 3. jee rome sowie ease Tropidia, Meig. 
CC.— Face not carinate. 
D.—Third segment of the abdomen in the male very much contracted, cy- 
lindrical, the hind femora much thickened, with a bifid spine below at 
the tip. Eyes very large, face small............... Senogaster, Macq. 
DD.—Hind femora more or less thickened, with spines or bristles below, 
never with a bifid spine near the tip. 
#. —Hind femora very much thickened, anterior cross-vein rectangular,.... 
Syritta, St. F, & Serv. 
HE.—Hind femora never remarkably thickened, hind coxze often with spin- 
ous process; cross-vein always oblique..............0. Xylota , Meig. 
BB. —Uarge pilose species, the abdomen always abundantly pilose. 
F.—Scutellum, . margin. of thorax. and pleurz with bristly hairs; face 
distinctly tuberculate; femora slender, abdomen without yellow 
MALKIN ES) alo vein Oe Aa) SESS ene revs ieee aenine ol Pryscunleni ye Rond. 
FF. —Thorax. wholly without bristly hairs. 
G.—Face short, not produced, concave from antennz to i not tuber- 
culate, transversely arched; hind femora more or less thickened. 
Jf ===) Noval yaavein GlOMNBHS gs SG Sono nec é Brachypalpus, Macq. 
HH.—Abdomen yery broad, thorax densely pilose, very large species. 
Pocota, St. F. & Serv. 
@G.—Face produced, longer than the front. 
