104 



in certain lights. Hypopygium rather large ; its lamellae and inner appendages 

 black, the lamellae large; when closely appUed to the hypopygium they are 

 cut off rather straight on apical margin so as to give the hypopygium a truncate 

 appearance, the hairs on their margin small, black; central filament and its 

 sheath testaceous black. 



Fore coxae yellow, sometimes with a blackish spot at base on outer surface, 

 anterior surface with small black hairs, middle coxae black with yellow tips, 

 posterior pair largely yellow, their base blackish. All femora, tibiae and fore 

 tarsi yellow, the latter sHghtly darker toward their tips; middle tarsi black 

 from the tip of the first joint; hind tarsi infuscated almost to their base. The 

 row of little bristles on fore tibiae quite conspicuous, but not reaching the base; 

 middle tibiae with one large bristle on lower anterior edge, and about five on 

 upper surface. Hind tibiae with six large bristles in two rows on upper surface 

 and two or three small ones below, their tips very slightly darkened on inner 

 side. Fore tarsi slightly longer than their tibiae, their joints as 28-12-10- 

 7-8; joints of middle ones as 37-22-18-11-10; those of hind pair as 28-35- 

 23-15-11. Calypters and halteres pale yellow, the former with black cilia. 



Wings dark grayish, sometimes tinged a little with brown; tip of third vein 

 bent backward so as to approach fourth a little; fourth vein ending in the 

 apex of the wing; last section of fifth vein about one and three-fourths times as 

 long as the cross-vein. 



Described from one male (holotype) taken at Machias, Maine, 

 July 20, by C. W. Johnson; one male taken at Hampton, New 

 Hampshire, September 30, by S. A. Shaw; two males taken 

 in New York, one at Old Forge, Long Lake, August 23, by 

 Shannon and Sibley, and one at McLean Bogs, Tompkins Co., 

 May 30, by M. D. Leonard. 



Holotype in collection of the Boston Society of Natural History. 



This differs from Gymnopternus frequens Loew in the form of 

 the lamellae, those of the latter being much smaller and widest in 

 the middle, making the hypopygium appear mpre pointed at tip; 

 Gymnopternus obtusicauda is also a little larger and the posterior 

 tarsi and wings are of a darker color. 



Gymnopternus vemaculus, new species. 



cf. — Length 3.7-4 mm.; of wing 4-4.5 mm. Face moderately wide, 

 whitish. Front blackish, thickly covered with white pollen, which usually 

 conceals the ground-color. Palpi and proboscis black. Antennae wholly 

 black; third joint about as long as wide, pointed at tip. Orbital cilia wholly 

 black. 



Thorax and abdomen dark green, almost greenish black, shining; pleurae 

 dulled with a little gray pollen. Hypopygium black; its lamellae black or 

 testaceous, sometimes yellowish at base, narrow, fringed with short black 

 hairs; when closely applied to the hypopygium they give its apex a somewhat 

 obtuse appearance; the central filament and its sheath yellowish testaceous. 



All coxae black almost to their tips, immature specimens with the anterior 

 pair more yellowish brown; fore coxae with minute black hairs on the anterior 

 surface and black bristles at tip. Trochanters, femora and tibiae wholly 

 yellow; fore tibiae with the usual row of little bristles small, they do not reach 

 the base, but where they end there are two larger bristles; middle and hind 

 tibiae each with two conspicuous bristles on lower anterior edge, the former 

 with about five, the latter with about seven large bristles on upper surface. 

 Fore and middle tarsi yellow, becoming infuscated toward their tips; last joint 

 black; they are a little longer than their tibiae. Hind tarsi more or less 

 infuscated from the tip of the first joint, sometimes only the tips of the first 

 two, and the whole of last three joints darkened. Joints of fore tarsi as 



