178 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.48. 



parafacials naked, cinereous. Eyes bare. Thorax opaque, ochra- 

 ceous, marked with four slender brown longitudinal vittae. The 

 inner pair slightly, the outer broadly interrupted at suture and 

 vanishing before posterior third of post-sutural area. Scutellum 

 opaque cinereous, its suture with the mesonotum narrowly shining 

 black; bearing two pairs of long marginal and a long cruciate apical 

 pair. Post-sutural bristles four; sterno-pleurals three. Abdomen 

 (pi. 6, fig. 3) ochraceous cinereous, slightly wider than thorax at 

 base, saggitate in form. Apex rather acute. Four segments visible, 

 exclusive of the very short basal one, first segment bearing a median 

 black spot which expands at base beneath scutellum, extending 

 caudad almost to but not touching posterior margin of segment, 

 usually inclosing a linear median ochraceous spot on its apical third ; 

 second segment bearing a faint median longitudinal band expanding 

 and becoming more distinct at posterior margin of segment, which 

 it does not touch. Third and fourth segments, including hypopy- 

 gium, immaculate except at bases of principal macrochaetae, which 

 are surrounded by a blackish ring. In some specimens segments 

 1 and 2 bear triangular black spots at bases of lateral marginal 

 macrochaetae. First abdominal segment destitute of median mar- 

 ginal bristles, second segment bearing a stout pair of marginals. 

 Third and fourth segments bearing both discal and marginal macro- 

 chaetse. Hypopygium of the male visible, that of female concealed. 

 Tibiae and femora, including coxae, reddish, yellowish pollinose. 

 Tarsi black, pul villi dusky, front claws of male elongate. Squamae 

 yellowish. Wings rather long, grayish hyaline. Longitudinal and 

 cross veins margined with a scarcely perceptible brownish stain. 

 Veins brownish. Costal spine obsolete. Bend of fourth vein abrupt, 

 destitute of stump or wrinkle. Apical cell open in margin of wing 

 and with a distinct neck at apex. Third vein bearing two or three 

 bristles at base only. In greasy specimens (and Dexiids, usually 

 become so) the median band on second abdominal segment appears 

 distinctly black. 



Habitat. — Open mesa, Koehler, New Mexico. 



Type:— Feme!*; Cat. No. 18341, U.S.N.M. 



This species is usually found sitting upon the ground on low her- 

 biage and is very common. One specimen seemingly identical with 

 this standing in United States National Museum (from Custer County, 

 California), as melanocera Desvoidy. The original description of 

 that species says "Antennae black," and is exceedingly brief. The 

 present species has yellow antennae and is evidently distinct. 



