1910] Melander — The Genus Tachydromia 57 
Tachydromia maculipennis Walker. 
Walker, List Dipt. Ins. in Coll. Brit. Mus., il. 507 (1849). 
Loew, Cent. v., 74 (1863) Tachypeza pusilla Q. 
Melander, Trans. Am. Ent. Soc. xxviii. 228; and 229, f. 51 (pusilla); and 204, 
f.1. (Phoneutisca bimaculata, Dakota specimens) (1902). 
Coquillett, Proc. Ent. Soc. Wash. v. 266 (1903) Phon. bimaculata. 
Aldrich, Catalog N. Am. Dipt., 310 (1905), Phon. bimaculata. 
Length 2mm. Shining black, antennae, palpi, proboscis and halteres also 
black, no pruinose spots on thorax. Outer joint of antennae short-conical, 
the arista two times the length of the antenna, almost terminal. Humeral 
swellings prominent, well constricted from the central portion of the thorax; 
no notal bristles; scutellum with four marginal bristles, the outer pair short. 
Hypopygium swollen, black hairy, the last ventral segment with a conspicuous 
fringe of black bristles. Legs largely blackish, the coxae, trochanters, and 
base of the femora paler; front tibiae and tarsi more or less yellowish; the 
last two tarsal joints black. Halteres whitish. Wings with a brownish cloud 
filling the submarginal and first posterior cells; the two cross veins approxi- 
mate. 
The type of this species, now in the Museum of Comparative 
Zoology, Cambridge, Massachusetts, was collected by LeBaron in 
Illinois. Ihave specimens before me from Chicago, Illinois, Milwaukee, 
Wisconsin, Atherton, Missouri (C. F. Adams) and Brookings, South 
Dakota (J. M. Aldrich). Dr. Hough has taken the species at New 
Bedford, Massachusetts. Mr. C. W. Johnson records pusilla from 
New Jersey in Smith’s Catalog. The synonymy of this species is 
discussed in the introduction anted, page 52. 
Tachydromia simplicior Wheeler and Melander. 
Wh. and Mel., Biologia Cent. Am., Dipt. Suppl. 375 (1901) Phoneutisca. 
Melander, Trans. Am. Ent. Soc. xxviii. 205, f. 6. (1902) Phoneutisca. 
Length 1.5mm. _ Body shining black, legs entirely yellow. Antennae short, 
the outer joint minute, smaller than the basal joint, the arista sub-dorsal. 
Palpi pure white, moderately broad. No bristles on mesonotal disc; scutel- 
lum with a pair of well separated marginal bristles; humeri well constricted 
and prominent; the sides of the thorax are very lightly pruinose, but there 
is no pruinose spot above the front coxae. Abdomen depressed, brownish 
hairy, the hypopygium small, terminal. Legs including the coxae yellow. 
the hind femora a little infuscated apically. Halteres yellow. Wings nearly 
hyaline, a very faint darker streak passes longitudinally through the middle 
of the wing; marginal cell short, submarginal cell full, third and fourth veins 
divergent. 
