120 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. G3. 



cent basall}-; last four tergites united one-fourth as long as the sec- 

 ond, becoming abruptly narrowed apically; tergites three to five 

 subequal, very short, apparently unsculptured; sixth tergite as long 

 as four and five united, broadly transverse, subacute apically; wings 

 hyaline, with long fringes of cilia at their margins. Reddish brown; 

 antenna, except club, mandibles and legs, yellow; antennal club 

 brown. 



Type locality. — Washington, District of Columbia. 



Paratype-locality. — St. Louis, Missouri. 



Type.—Csit. No. 2268, U.S.N.M. Type selected. 



Host. — Cecidomyia, species in squash. 



Redescribed from type material, eight females, in the United States 

 National Museum. Types from Washington were not found in the 

 collection. 



4. LEPTACIS PENNSYLVANICA. new species. 



Plate 1, fig. 4. 



Female. — Length 0.80 mm. Elongate, with the thorax strongly 

 compressed; head wider than the thorax, twice as wide as long, 

 attached rather low on the prothorax; frons shining, aciculate, striate 

 above the antennae; head seen from in front scarcely wider than high, 

 flattened above; vertex bordered posteriorly by a sharp oarinae; occi- 

 put faintly shagreened; thorax strongly convex above, more or less 

 arched, over twice as long as wide, pubescent and finely shagreened 

 dorsally; mesonotum truncated apicall}^, its margin projecting over 

 the base of the scutellum; soutellar fovea absent; notauli absent; sou- 

 tellum shaped as in minutus but with the spine truncate apically and 

 with the posterior face of the scutellum perpendicular, forming a 

 right angle with the lower surface of the spine ; abdomen a little wider 

 than the thorax, as long as the head and thorax united, elliptical, 

 strongly convex above and below, about twice as long as wide; sec- 

 ond tergite two-thirds as wide as long, polished, narrowly pubescent 

 at base; last four tergites united half as long as the second, polished; 

 tergites three to five subequal, longer than in minutus; sixth tergite 

 as long as four and five united, transverse, rounded apically; wings 

 hyaline, with long cilia. Shining black; proximal half of scape, tro- 

 chanters, front tibae, all tarsi (except last joint of each), middle and 

 posterior tibiae basally, yellowish; middle and hind tibiae for the 

 most part, and the last joint of each tarsus, light brown. 



Type locality. — Carlisle, Pennsylvania. 



Type.—C&t. No. 25452, U.S.N.M. Nine paratypes in Collection 

 Fouts. 



Described from sixteen female specimens collected by the author 

 on the flowers and flower buds of milkweed. The dates of collection 

 range from the 1st to the 21st of July. Eight specimens were col- 

 lected on July 1 , 1918; one on July 2, 1918; and seven on July 21, 1920. 



