298 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. 



species in the ornamentation of the four anterior tarsi of the male, and 

 at the same time very different, even in those characters. 



Male. — Pile on the face pale yellow, sometimes yellowish- white, black 

 above the mouth ; lower part of the head j^osteriorly and front part of 

 the chest with yellowish- white pile ; thoracic dorsum, including even 

 the base of the scutellum, covered with a yellowish-brown pollen, except 

 at the four corners, which are black ; three stripes on the dorsum are less 

 pollinose, and therefore darker; the intermediate one geminate, and ab- 

 breviated posteriorly; the lateral ones broad, abbreviated, and rounded 

 anteriorly, converging toward each other posteriorly, in front of the 

 scutellum ; abdomen black, shining, clothed on the sides with dense yel- 

 lowish pile, gradually diminishing in length toward the tip. Legs black ; 

 tibiae reddish, black at tip ; front tibise often altogether black. Joints 

 2-5 of the front tarsi densely beset with silvery- white recumbent hairs 

 along the outer and upper side only, and therefore not parted in the 

 middle (in the two preceding species, the silvery hairs are found both on 

 the outer and inner side of the upper part of the tarsi, and are parted in 

 the middle); some silvery pile on the outside of the first joint ; the two 

 last joints of the middle tarsi with a disk-shaped, flat brush of black 

 bristles, as in the two preceding species ; pulvilli blackish-brown ; all 

 the femora and the four posterior tibiae beset with long pale yellowish 

 pile. Wings grayish-hyaline. 



Female. — Like the male, except in the sexual ornamentation of the 

 front and middle tarsi, etc. Abdomen black, shining, the sides densely 

 beset with pale yellowish-white pile, through which, on segments 2-5, the 

 white pollinose spots in the hind corners of the segments are visible. 

 Will be easily distinguished from G. calUpedilus 9 by its pollinose scu- 

 tellum, less densely pollinose thoracic dorsum, more yellowish pile of 

 the face and chest, etc. Length, ^ 5 12-13™°^. 



Sab. — Morino Valley, Kew Mexico, July 1 (Lieut. W. L. Carpenter) ; 

 Spanish Peaks, June (the same) ; Cache Valley, Utah (C. Thomas) ; 

 divide between Idaho and Montana. Six males and two females. 



4. Cyrtopogon montanus Loew, Berl. Ent. Zeitschr., 1874, 362. 



^'■Male. — Ater, tibiis tamen posticis prseter basim et apicem rufis, pilis 

 nigris et albis vestitus, abdomiue toto nigro-piloso, segmentis 2-5 singu- 

 lis postice fascia albo-pollinosa oruatis, alls cinereo-hyalinis. Long. corp. 

 3f lin.; long. al. 2| lin. 



(Translation.) — "Deep black; hind tibiae dark reddish, brownish-black 

 at base and tip; the upper half of the occiput and the front with long 

 black hairs. The two first antenual joints with scarce, at least in part 

 whitish hairs ; third joint wanting. The dense mystax, reaching up to 

 the antennae, is black on the sides and on the lower part of the face ; its 

 inner partis white. Palpi with black hairs; lower half of the occiput 

 and the mentum with white hairs. The thoracic dorsum seems to have 

 been principally covered with grayish pollen ; the specimen is too badly 

 preserved to warrant a positive statement. The hairs on thoracic dor- 



