ir>2 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



three inteiTiipted bauds; tlie tirst two pairs of spots larj^e ; the third 

 narrow, either a light transluceut yellow or an inconspicuous bluislij 

 in some speciiueus the yellow becomes more or less contliteut, so that 

 the dorsum is chieiiy yellow; venter wholly black, with a li^iht yellow 

 median transverse band, or wholly yellow, except the tip. Legs black ; 

 tibiae on the proximal third yellowish, metatarsi and sometimes the 

 second and third joints red ; wings hyaline ; stigma brownish. 



Thirty specimens (Comstock, Coquillett, Morrison). 



This species shows very great variation in color and markings. In 

 isolated specimens one would scarcely consider the ditierences to be less 

 than specitic, but the variations are inconstant, and do not seem to 

 be of more than varietal worth. Some specimens agree well with 

 Macquart's description and Hgure, while others have still more yellow, 

 as in Say's specimens. A very dark variety In which tlie thorax is 

 clothed with black pile and wholly lacking the yellow of the sides and 

 before the scutellum, the venter wholly T^ithout yellow and the antennae 

 black, may be distinguished as variety lentiim. 



In nine specimens from Montana (Professor Comstock) the size is dis- 

 tinctly smaller, the facial stripe is narrower and distinctly separated 

 from the black at the base of the antennae by a yellow interval, the 

 frontal triangle is yellow along the eyes and the outer part of the sec- 

 ond vein is less sinuous. These differences are i^ossibly specific. 



Copestylum limbipennis, n. sp. 

 Habitat. — Mexico ! 



9 . Length, 9'"'". Face black, clothed with short, white pile, with 

 two rather narrow yellow stripes, convergent below. Front black, with 

 short, white pile, and a small yellow spot on each side near the middle. 

 Antennae brown, second joint red; third joint not twice the length of 

 the second, not one-half as long as the arista; arista long, black, grad- 

 ually and symmetrically widened from the base to near the tip. Eyes 

 with short, not abundant, white pile; in the middle with an elongate, 

 vertical stripe of black pile. Thorax shining black, wath short, white 

 pile; a small spot behind the humeri, a slender intra-alar vittula, and 

 two small spots in front of the scutellum, yellow; the pleura? with a small, 

 vertical yellow spot on the meso-pleur;e. Scutellum yellowish brown, 

 subtranslucent. Abdomen black; an oval, obli(iue spot on each side of 

 the second segment, toward the front, a larger semi oval spot on each 

 side of the third segment in front, and the fourth sef>ment almost wholly 

 yellowish red or reddish yellow; venter black, with a i)air of large oval 

 spots on the posterior part of the second segment. Legs deep mahog- 

 any-black. Wings hyaline, broadly brown in front, the brown begin- 

 ning gradually from near the origin of the second vein, and tilling out 

 uniformly the costal, subcostal, marginal, and all of the submarginal 

 cells, and clouding the posterior margin of the third vein, the anterior 



