270 DIPTERA 
upper ; wings pictured usually with crossbands, basal cells long, 
ihe posterior crossveim. located near the middle of the wing, 
marginal cell long, the second section of the costa usually much 
longer than the third section ; polished species with the thorax 
narrowed in fro (Pl. 4, Fig. 29). . . . . . 
Front. relatively broad and. V-shaped, its sides bowed outwardly ; 
palpi oval or elongate oval, white, densely hairy, varely with an 
apical sela, longer than the short proboscis; eyes contiguous below 
the antenna. obliterating (he face, the lower facets large. the 
antennal. emargination relatively deep; wings nearly or quite 
hyaline, basal cells short, the posterior crossvein. near the. basal 
third of the wing, second and third sections of the cosia usually 
subequal ; species sometimes follinose and with quadrate thorax 
(Pi. 4, Fig. 85). . . . SOS CE T 
6. First basal cell equal to or. longer than he PASA id cell nol 
formed ; opaque. pollinose species ; eyes widely separated on face 
and front; two pairs each of ocellar and vertical bristles A Ee 
First basal cell shorter than the second, if the basal cells are subequal 
the eyes are close together either above or beneath the antenne or 
the middle tibig are spurred ; abdominal pits, especially the dorsal 
oues, rarely visible; one pair of diverging ocellar. bristlles and 
usually one pair of verlicals .... . . v dd RC AE 
7. Arisla apical ; humeri constricted ; legs not evidently bristly ; cheeks 
linear, face narrower than. the front ; ocellar bristles diverging ; 
nolum with coarse hairs but no strong anterior dorsocentrals ; 
abdominal segments without dorsal pits... .— . E AER 
Arista subapical or dorsal; humeri not. constricted ; s bristly ; 
cheeks at. least one-fourth the eye-height, face at least as broad. — 
as the front ; abdomen with dorsal as well as lateral fittings . 
8. Mesonotum with diíscal bristles; last joint of the antenne bare and 
with a subapical bare arísta; eyes bare; lower ocellar bristles 
comverging. . . . : i. 
"No discal bristles on the VRE third end joint icu dd 
bearing a dorsal pubescent arista; eyes pubescent; lower ocellar 
bristles diverging . .. Eie Y 
9. Wings as long as or DAME the dine, their hind. margin 
ciliate . 
Wings aborted, ps MR eC as Pis as " irpo At pes on 
their hind margin; arista dorsal (Pl. 7, Fig. 71). . . 
10. Cheehs one-third. the eye-height ; first vein. long, ending at. two- 
thirds the length of the wing, first sectíon of (he costa not ciliate; 
femora, especially the hind fair, with numerous strong. bristles ; 
iwo presulural dorsocentrals present; antenue. éainly three- 
jointed ; fulvilli large (Pl, 7, Fig. 70). . . . . : 
Cheeks narrower, usually one-sixth the eyc-height ; first vein "nr 
near the middle of the wing, the first section of the costa usually 
Genus Tacnvpkowra, Meigen. 
Genus TacHYEMPIS, nov. gen. 
Genus TuiNopRowrA, Melander. 
Genus CorLospoNEURA, Melander. 
