FAM. EMPIDIDJE 139 
Dipt. Man. p. 226 (1908); Coquillett, Proc. U. S. Nat. Mus. Vol. 37, p. 582 (1910); Lundbeck, 
Dipt. Dan. Vol. 3, p. 98 (1910). 
Pachymerina, Macquart, Hist. Nat. Dipt. Vol. r, p. 333 (1834), Vol. 2, p. 657 (1835); Boitard, Man. 
Ent. Vol. 3, p. 319 (1843); Bigot, Ann. Soc. Ent. France (3), Vol. 5, p. 561 (1857); Coquillett, 
Proc. Ent. Soc. Wash. Vol. 5, p. 254 (1903); Proc. U. S. Nat. Mus. Vol. 37, p. 582 (1910). 
Platyptera, Meigen, Illiger Mag. Ins. Vol. 2, p. 269 (1803); Curtis, Brit. Ent. Vol. 8, p. 18, 2 (1824). 
Platypterygia, Stephens, Syst. Cat. Brit. Ins. Vol. 2, p. 263 (1829); Westwood, Gen. Syn. p. 131 
(1840); Coquillett, Proc. Ent. Soc. Wash. Vol. 5, p. 256 (1903); Proc. U. S. Nat. Mus. Vol. 37, 
p- 592 (1910). 
Polyblepharis, Bezzi, Deusche Ent. Zeitschr. 1909, Beiheft, p. 95 (1909). 
Pterempis, Bezzi, ibidem, p. 87 (1909); Lundbeck, Dipt. Danica, Vol. 3, p. 108 (1910). 
Xanthempis, Bezzi, Deutsche Ent. Zeitschr. 1909, Beiheft, p. 88 (1909); Lundbeck, Dipt. Danica, 
Vol. 3, p. 85 (1910). 
Characters. — A dominant and variable genus whose species range from three to ten milli- 
meters in length. More or less slender, sometimes abundantly hairy, sometimes nearly bare, usually 
black though often cinereous or yellow, pollinose or shining. Head narrower than the thorax, globular, 
or in Xanihempis pear-shaped, due to a conical development of the occiput; eyes contiguous on the front, 
or subcontiguous or fully separated, when contiguous the upper facets usually larger than those below, 
when separated the facets uniform, eyes of female always separated and with uniform facets; face usually 
broad, the lower edge somewhat ridged at the epistome, in .Lissempis the face is narrow; antennz 
generally longer than the head, ihserted at or a little above the middle, distinctly three-jointed, the first 
joint usually longer than the second and both more or less cylindrical, the third joint lengthened, 
compressed conical, with a terminal two-jointed style whose apical part is longer than the basal segment 
and tapers; proboscis at least as long as the head, usually much longer, strong, vertical or slightly 
infléxed, in Acallomyia slender and obliquely projecting, labium of variable length, palpi cylindrical. one- 
jointed, short, extending rather upward; occipital hairs biseriate or abundant. Thorax rather large, not 
greatly convex, generally vittate to mark the acrostichal and dorsocentral spaces, prothorax of 
Xanthempis lobosely broadened, chaetotaxy very variable, sometimes the thorax is abundantly furnished 
with fine hairs, sometimes the dorsocentrals and acrostichals form definite single rows, sometimes the 
acrostichals are entirely absent, humeral, posthumeral, notopleural and supraalar bristles variable but 
usually present; metapleuree always with some hairs or bristles, pectus with or without hairs. Abdomen 
rather slender and long, tapering in the female but in the male generally with quite prominent pygidium, 
which comprises two pairs of lateral valves a ventral piece and a long and slender or short and thick 
penis; in some species the last ventral segment of the male is pronged. Legs of the female often ornate 
with scales, sometimes the males have apophyses about the hind knees or on the hind trochanters, 
otherwise the legs are more or less hairy and bristly. "Wings generally narrow but in some females 
(e. g. E. borealis) unusually broad, costa stopping at the end of the wing, basal bristle present or absent, 
auxiliary vein straight and incomplete, not reaching the costa, third vein forked, discal cell usually 
rather small, emitting three veins, of which the first may be shortened (CoftofAlebia), anal cell short and 
narrow, the anal crossvein abruptly reflexed, the anal vein separate from the anal cell, anal angle of the 
wing usually more or less rectangular, sometimes obtuse, sometimes strong, auxillary incision distinct, 
alula small or absent, fringe of the calypteres variable. 
Type species : E. jennipes, Linneus (Pl. 5, Fig. 48, 49), so designated by Latreille, 1810. 
Curtis, Westwood and Rondani selected E. /essellata, Fabricius, 1794, as the type, and this course 
unfortunately has been usually followed by European dipterists. Bezzi has erected the subgenus 
