1910] Melander — The Genus Tachydromia 57 



Tachydromia maculipennis Walker. 



Walker, List Dipt. Ins. hi Coll. Brit. Mus., iii. 507 (1849). 



Loew, Cent, v., 74 (1863) Tachypeza pusilla Q . 



Melander, Trans. Am. Ent. Soc. xxviii. 228; and 229, f. 51 (pusilki); 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 2 mm. 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 I^eBaron in 

 Illinois. I have 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 Xew 

 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 antea, page 52. 



Tachydromia simplicior Wheeler and Melander. 



Wh. and Mel., Biologir Cent. Am., Dipt. Suppl. 375 (1901) Phoneutisca. 

 Melander, Trans. Am. Ent. Soc. xxviii. 205, f. 6. (1902) Phoneutisca. 



Length 1.5 mm. 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 midille 

 of the wing; marginal cell short, submarginal cell full, third and fourth veins 

 divergent. 



