350 ERNEST A. BACK. 



a reddish vittas on the anterior side, often connected at the apex with 

 a shorter one on the posterior side; wings deep brown or blackish. 

 Female. — Varies from a black form similar to the male, to one with 

 thorax, abdomen and legs reddish, and with much lighter wings. 



9- — Black; face, front and occipital orbits silvery-white pruinose; 

 palpi, antennae and the proboscis black, hairs and bristles on these. 

 the mystax, frontal and occipital bristles, clear or sordid white, 

 Dorsum of thorax, pleurae, scutellum and coxae densely yellowish- 

 gray or grayish pruinose; the dorsum with three broad blackish stripes, 

 the median one divided by a fine grayish line. All the bristles of the 

 thorax sordid white, the short hair on the anterior portion of the 

 dorsum black; pleurae bare, without pile or bristles except before the 

 yellowish halteres. Abdomen robust, tinged with blue, the sides of 

 the first segment and the posterior lateral margins of the three follow- 

 ing grayish pruinose; genitalia wholly black. Hair of the abdomen 

 longer on the sides and venter black, except on the pruinose areas, 

 where it is often white. Legs black, the fine bristles of all the coxae 

 white; all the femora before with a narrow reddish stripe sometimes 

 connected over the apex with a similar stripe behind; basal portion of 

 the segments of the middle and hind tarsi reddish. Bristles on the 

 fore tibiae and on all the tarsi sordid white; on the middle and hind 

 tibiae black; the white hair-like pile on the hind femora very notice- 

 able. Wings brownish or blackish, darkest along the costa and at the 

 apex; fourth posterior cell closed at the margin or narrowly open. 



$. — Reddish-brown; antennae, palpi and base of proboscis of same 

 color. Bloom of head and thorax more golden and the stripes of the 

 thoracic dorsum less distinct, and all the pile and bristles of the entire 

 body yellowish. The posterior lateral margins of the abdominal seg- 

 ments 1-5 and the venter of segments 2-4 whitish pruinose; the pleurae 

 and lateral spots on all the segments and the venter black. Legs 

 wholly reddish-brown; all the femora above with a black vitta not 

 reaching the apex. Wings much paler than in the male. 



Type.—U. S. N. M., Cat. No. 6313. Type series, seven 

 males and seven females. 



Habitat. — Cuero (June 6), Columbus (E. A. Schwarz), and 

 Runge (J. C. Crawford, Aug. 14), Tex.; Ardmore (C. R. Jones, 

 July 11), Okla. (I. T.). 



I have seen the type series and also a series of three males 

 and nine females belonging to the U. S. Bureau of Entomology 

 and now also at the National Museum. While the male is 

 nearly constant in color, I found a gradation in the female 

 from a black form similar to the male to a reddish-brown 

 form like the one described above. This gradation is best 

 brought out in the Bureau material bearing the "Hunter" 

 labels. 



