136 BULLETIN BROOKLYN ENTOM. SOC. VOL. VII. February 1885. ] 
late, third longitudinal vein gently curved, the fourth vein joins the third 
a considerable distance before the tip; anterior cross-vein usually near 
the base of discal cell; legs slender, hind femora never thickened. 
A.—Arista very densely plumose, appearing like a solid mass....Copestylum, Macq. 
AVA Arista steathenyapiuimOSe i... 1)./) cate eee Oley rahe) seat Volucella, Geof. 
ERISTALINAE. 
Large species, uniform in color or more or less variegated, thinly or 
thickly pilose; third joint of antennz short, arista bare or thinly pilose; 
abdomen short, broad, arched; hind femora sometimes much thickened; 
marginal cell of wings closed and petiolate; third longitudinal vein with 
a deep concavity into the first posterior cell; anterior cross-vein near or 
beyond the middle of the discal cell, oblique. 
A.—Thorax never with yellow spots. 
B.—Frontal triangle of male strongly protuberant... ..... -Doliosyrphus, Bigot. 
BB.—¥rontal triangle of male evenly arched.......... Sea Eristalis, Latr. 
AA.—Thorax with yellow spots. 
(¢.—Hind femora without a projection below.............. Pteroptila, Loew. 
CC.—Hind femora with a projection below near the end. (Milesia.) 
MALLOTINAE. 
Mostly large, thickly pilose species; antennz short*; the third joint 
-not longer than broad, arista basal, bare; hind femora thickened; marg- 
inal cell of wings open, third longitudinal vein deeply curved into the 
first posterior cell, anterior cross-vein at or beyond the middle of discal 
cell, oblique; hind femora thickened. 
A.—Arista plumose (Sericomyine). 
AA.—Arista bare. 
B.—F ace with a longitudinal ridge in the middle; hind femora strongly thicken- 
ed and with an angular protuberance below, near the end 
Tropidia, Meig. 
BB.— Face not distinctly carinate; tuberculate or rounded. 
C.—Hind coxee and tip of hind tibie in the male with spurs; eyes of male 
broadly separated......... 84. ETAL aS ree (Polydonta ||) Triodonta, 
CC.—Hind coxze and tip of hind tibiz in the male without such spurs, or if 
so, the abdomen is elongated and cylindrical, 
D.—Thorax and scutellum very densely pollinose above; the face in the male 
more tuberculate than in the female .............. Pterallastes, Loew. 
DD.—Thorax and scutellum not densely pollinose above. 
F,—Third joint of antennze: broad, thorax not vittate. 
Bi Mhickly spilosen:. 2. saci Meerennek totaal ere vee eae Mallota, Meig. 
* Chrysotowum may be sought for here: the antennze are elongate, and the 
dorsum of the thorax has yellow lateral stripes. 
