OSTEN SACKEN ON WESTERN DIPTERA. 219 



5. Tabanus insuetus n. sp. — Belongs apparently to the subgenus 

 Atylotus. Eyes pubescent, although in the female specimens the pubes- 

 cence is often hardly perceptible ; in life, pale olive-green, with a single 

 very narrow brown stripe in the middle (distinct even in dry speci- 

 mens) ; no vestige of an ocellar tubercle; frontal callosity rather small, 

 variable in size, narrower than the front; third anteunal joint rather 

 broad and short, with a short and stout annulate portion ; palpi stout 

 at base ; first posterior cell broadly open ; base of upper branch of third 

 vein knee-shaped, in many specimens with a stump of a vein. All these 

 characters would justify the location of the species in that sub-genus; 

 the discovery of the as yet unknown male will have to decide it. 



Female. — Face and front yellowish-gray ; cheeks with pale hairs ; front 

 with short black hairs ; a fringe of such hairs on the upper edge of the 

 occiput. Front broad (in most specimens; much narrower in others) ; 

 frontal callosity narrower than the front, rather small, and variable in 

 shape ; usually another black, shining spot above it. Palpi short, stout 

 at base, pale yellowish or yellowish- white, with black pile. Antennas 

 pale brownish-reel ; annulate portion of third joint sometimes^ but not 

 always, black or brown. The black ground-color of the thorax is partly 

 concealed under a gray pollen ; vestiges of longitudinal gray lines are 

 visible anteriorly; a pale golden, sometimes whitish, appressed, rather 

 scarce, pubescence, and black, erect pile clothe the dorsum. Pleurae 

 gray, with pale gray hairs. Abdomen in well-preserved specimens 

 with three rows of yellowish-gray spots, formed by an appressed 

 pubescence ; the triangles of the intermediate row large, Occupying the 

 whole breadth of the segment ; the spots of the lateral rows are oblique, 

 prolonged laterally along the hind border of the segments (well-pre- 

 served specimens seem rarely to occur ; in the worn specimens, the ab- 

 domen appears as grayish-black, somewhat reddish on the sides of the 

 first two segments, and with but vestiges of the appressed yellowish- 

 white pubescence and of the abdominal spots). Venter uniformly 

 j yellowish-gray. Feet variable in coloring, pale reddish-yellow, with 

 I blackish (seldom pale) femora and tips of tibiae ; tarsi blackish, the two 

 I posterior pairs paler at base. Costal cell and stigma more or less tinged 

 with brownish-yellow ; upper branch of third vein often, but not always, 

 with a stump of a vein. Length 12-13 mm . 

 Hab. — Webber Lake, Sierra County, July. 2 1. Twelve females. 



6. Tabanus ^egrotus n. sp.— Female. — Altogether brownish-black; 

 wings immaculate ; third antennal joint very broad at base. Length 



I l9-20 mm . 



Front, face, and cheeks clothed with a dense brown pollen, hiding the 

 ground-color; front moderately broad; frontal callosity subobsolete, 

 iilat, not shining, prolonged above in an opaque line ; cheeks with if own 

 j hairs; palpi dark brown; antennas black, third joint very broad, ex- 

 panded, and rounded on the under side, and with a projecting upper 

 3 H B 



