114 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



both sides at the midline, second inclosing a pair of dorsal black 

 spots, third with a pair of anterior emarginations replacing the 

 spots of the second, fourth and fifth with a shallow emargination on 

 either side the midline, sixth and seventh with a medial spot apicaUy, 

 lateral spots on stemites 1-5 connected on one and two by narrow 

 apical lines, small medial posterior spot on two, spot on anterior and 

 middle coxae below, femora except more or less basally, tibiae, 

 and tarsi, yellow. The spots on the scutum and scutellum are white. 



The flagellum is testaceous below and is neither spinose nor den- 

 tate. Segments 4-11 bear small pits on the posterior surface and 

 the ultimate segment is short, scarcely exceeding the length of the 

 preceding segment, curved and rounded at the apex. The eyes are 

 widely separated and are sHghtly divergent above. The middle 

 femora are smooth. The second sternite bears a prominent median 

 tubercle shghtly curved posteriorly; the sixth bears a median, tri- 

 angular, pointed process whose ventral surface is flattened or sUghtly 

 concave, and the seventh bears a median carina that is bordered 

 basally on either side by a shorter one. 



Length. — 4-17 mm. 



The pubescence is pale, moderately long and dense, shortest on the 

 scutum and abdomen and about equally well developed on male and 

 female. The wings are hyaline and veins brown. The yeUow 

 markings have a greenish tinge and the black is intense, resembling 

 in this respect the color of B. helfragei. The lateral angles of the 

 median segment are somewhat prominent. The dark color on the 

 legs is irregularly distributed, especially on the tarsi. 



There is some variation in the maculations of the female; those 

 on the scutum may be reduced to short lateral lines above the base 

 of the wings; the fascia on the median segment may be interrupted 

 medially; the marking of the mesopleura may be reduced to a single 

 small spot; and the inclosed black spots on the second and third tergal 

 fasciae may appear as deep anterior emarginations. The female of 

 tliis species, which stands close to troglodytes Handhrsch, has the 

 labrum, scape of flageUum, and ultimate tergite black, whereas 

 troglodytes has these parts yeUow or maculated with yellow. On 

 the male the scutum, metanotum, and dorsum of median segment 

 are black; on troglodytes the metanotum and dorsum of median seg- 

 ment each bears a fascia and the scutum a pair of discal marks. 

 The genital stipites of the two also differ. 



Habitat. — Kansas, Texas. 



Number of specimens examined — Females, 7; males, 1. 



Type (female). — Allotype, and paratypes in the collection of the 

 University of Kansas. 



Paratype.—C&t. No. 19885, U.S.N.M. 



