85 



fourth vein quite strongly bowed, the first posterior cell widest at the middle 

 where it occupies two-sevenths of the wing-width; cross- veins at two-fifths the 

 wing-length, distance between the cross-veins two-thirds the length of the 

 anterior cross- vein; base of anal vein very weak. 



Holotype. — Boston, Massachusetts, June, 1914 (Melander). 



Platypalpus hians, var. fuscohalteratus, var. nov. 



Quite similar to the Western typical form except that the thoracic bristles 

 {i.e., one notopleural, one supra-alar, one prescutellar, one postalar, and four 

 scutellar) are black and that the halteres are decidedly dusky; face very short, 

 the epistome polished. Dark halteres are very unusual among the species of 

 Platypalpus. The Maine specimen has the third antennal joint largely yellow. 



Distribution. — Ithaca, New York; Capens, Maine (C. W. 

 Johnson); Sudbury, Ontario (H. S. Parish). 



Holotype. — Ithaca, New York (Melander Collection). 



Platypalpus holosericus, sp. nov. 



9 . — Length 3-4 mm. Robust, black, thorax entirely densely cinereous 

 pollinose, the ground color nowhere visible; bristles yellow, legs including the 

 coxae yellow, tibial spur large, epistome and face white pruinose; base of the 

 antennae yellow, the third joint ovate, two-thirds as long as the arista; posterior 

 cross-vein oblique, located beyond the anterior, first posterior cell narrowed at 

 the apex. Head densely cinereous pollinose, one pair of yellow vertical- 

 bristles present; front narrow, its sides parallel; antennae two-jointed, the outer 

 joint nearly twice as long as wide; palpi yellow, broadly oval, large, not hairy. 

 Mesonotal hairs rather sparse but evident, two dorso-central, one pair of each 

 of the other usual bristles; no glabrous pleural spot; abdomen shining black, 

 the lateral anterior angles of the segments with more or less evident triangular 

 cinereous marks, the lateral pits evident; ovipositor brown-pollinose. Front 

 femora with yellow flexor cilia, middle femora not setose behind; middle tibiae 

 two-thirds as long as their femora, tarsi weakly annulate. Veins pale, costa 

 not thickened, its second, third and fourth sections proportioned about 5: 5:1; 

 third vein nearly straight, ending at or beyond the wing-tip, the fourth vein 

 with a perceptible backward curvature, the first posterior cell widest near the 

 middle; posterior cross-vein separated from the anterior by a little less than the 

 length of the anterior; sections of the fifth vein proportioned 0.6: 0.9:1; anal 

 cross-vein forming an angle of fifty-five degrees, anal vein distinct but weak, 

 marginal cilia very short. 



Sixteen specimens: Forest Hills, Massachusetts, July (C. T. 

 Brues); St. John, New Brunswick, June (W. Mcintosh, in the 

 U. S. National Museum) ; Megantic, Quebec, June (C. H. Curran, 

 in Canadian National Museum). 



Holotype. — Forest Hills, Massachusetts (Melander Collection). 



Platypalpus pectinator, sp. nov. 



Length 3 mm. Black, mesonotum densely pubescent, shining, pleurae 

 pruinose except usual spot, bristles yellow, legs yellow, tibial spur minute, 

 tarsi not annulate, third antennal joint conical (cf) or ovate ( 9 ), cross- veins 

 meeting. Occiput cinereous, front and face nearly devoid of dust, shining, 

 sides of the front diverging above; palpi very large, orbicular, yellow, white- 

 pollinose on the outside, one short white pre-apical seta; antennae plainly three- 



