244 ERNEST A. BACK. 



lateral margins of the segments above and the venter usually black. 

 Legs yellowish-red, the basal half of the front femora are usually black. 

 The hind femora are thicker than the others. Dr. Williston (loc. cit.), 

 in speaking of a male specimen from Kern County, Cal., thinks it 

 strange that Osten Sacken did not mention "the closed and briefly 

 petiolate fourth posterior cell." In only one of the type specimens 

 from Idaho is the fourth cell barely closed at the margin, the rest are 

 open. This cell is variable. 



Type. — M. C. Z. Two male and two female type specimens 

 in Osten Sacken' s collection, and the two females in that of 

 Loew. 



Habitat. — -Type material all from Snake River, Idaho, 

 except one female from California. Kern County, California 

 (Williston). 



The female co-type from California has the face, front and 

 thorax, excepting three indistinct stripes on the thoracic dor- 

 sum, the coxae and neighboring region, proboscis, palpi and 

 basal segments of antennas (third wanting) reddish. It agrees 

 in size with the other type specimens, and probably represents 

 a variation. It answers quite well to the description of rufus, 

 but does not come near it in size. 



Myelaphus melas (PL X. fig. 3.) 



Myelaphus melas Bigot, Bull. Soc. Ent. France, 1882, No. 9, 112. 

 Myelaphus melas Williston, Trans. Am. Ent. Soc. XI, 5, 1884 

 (PL 5, figs. 1, la). 



$. — Length 14.5 mm. — Black, abdomen polished; halteres and pul- 

 villi, yellow; wings black, more dilute behind and at tip. 



Face smooth, polished, bare, in the middle on the tubercle, broadly 

 and indefinitely pitchy red; bristles on the oral margin yellowish- 

 white, with one or two black ones on the sides; beard short, sparse, 

 black. Front on the sides near the eye with a few short, black bristles. 

 Antennae wholly black; on the upper sides of the first and second 

 segments with a few short black hairs. Thorax deep polished black, 

 above with a blue reflection, the dorsum wholly without markings, 

 but covered with very short sparse black hairs; a minute spot on the 

 humeri red, and the post-alar callosities pitchy black. Pleurae very 

 smooth, polished, except on the upper part of the sternopleurae and 

 on the mesopleuras, where it is moderately thickly covered with short 

 pile, black above, whitish below. All the coxas on their outer sides 

 with sparse whitish pile, and at their lower ends with a few short 

 whitish bristles. Halteres yellow, the extreme base a little brownish. 

 Abdomen polished black, with very short, rather sparse black hairs, 



