FAM. EMPIDID/E 269 
SuBFAMILY TACHYDROMIINZE 
Characters. — Small species in which the neuration is greatly reduced. Head globular; eyes 
generally separated above the antenne, but in Symballophthalmus there contiguous, often more or less 
approached below the antenna in both sexes, in which case the lower facets may be larger, often 
pubescent ; antenne short, two- or three-jointed, the arista one- or two-jointed, usually hairy, generally 
apical but sometimes subdorsal; proboscis short, incurved or perpendicular, in the latter case more 
slender, in the former case strong at the base and pointed, no labella, palpi one-jointed, incumbent, 
often broad; vertical bristles usually well developed. 
Thorax stout and short as compared with the abdomen, often pubescent and with discal bristles, 
metapleurz bare; pygidium asymmetrical, with an unpaired upper valve. .Legs sometimes slender, as 
in Tachydromia, sometimes stout, as in Platyfalfus, coxze not long, middle legs sometimes raptorial and 
armed, femora often thickened. Wings with reduced anal angle, costa continuing to the fourth vein, 
auxiliary vein always rudimentary or imperfect. third vein unforked, no discal cell, that is, the discal 
cell is fused with the second basal, basal cells large, the first and second basals equal or the second 
longer, three posterior cells, anal cell weak or wanting, the anal vein incomplete even when best 
developed but most often wanting, anal crossvein if present perpendicular, when present the anal cell 
is shorter than the basal cells, usually no stigma, no alula. Calypteres closely united to the base of the 
wing and possessing a small fringe. 
TABLE OF THE GENERA AND SUBGENERA OF THE TACHYDROMIIN/E 
1. Thorax slender, much longer than broad, the humeri large, strongly 
coustricled ; broboscis vertical and slender, albi usually narrow ; 
legs slender, cursorial and mot brislly, front femora. usually 
Cas scere os WD E CO TOIT nA D eM M E 
Thorax broader, the humeri vavely lavge; legs hairy and. usually 
with bristles ov. sete ; proboscis usually inflexed and. stronger. at 
In2x DUsr DALDE HSHOI ORHE Dyüdds cR C M T I Ie. V. ee ie lá 6. 
2. 5 Manes and Aauekes- present; aretlal celo o o ru V o elm da CMT Eo. e 32 
Wings and halteres entirely lacking ..... ,.. . Genus PIELTAINIA, Arias. 
3. First basal cell evidently shorter than the second ; bach sube; Soul 
femora thichened. .... Wb vocvr ei ease NL Ade 4- 
First basal cell slightly longer than he second ; iiri "e outer B ieri 
of the anal cell present; yellow species with black head; last 
larsal joint broadened, femora slender... .. . . . . . Genus DysareTR1A, Loew. 
4. Anal crvossvein present; proboscis longer than ihe palpi; third 
antennal joint oval, with apical arista; front narrow, its sides 
parallel ; thorax elongate, navrowed anteriorly, mesonotum more 
or less pruinose ; wings more or less nebulous (Pl. 4, Fig, 831). Genus Tacnyrsza, Meigen. 
Anal crossvein completely wanling; proboscis often. shorter than the 
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5. Front narrow, ils sides straight and nearly parallel ; palpi narrow 
and elongate, but. usually shorter than the proboscis, subshining 
and usually with an apical seta; face linear ; antennal emargi- 
nation of the eyes small, lower facets but slightly larger than the 
