INSECUTOR INSCITL^i MENSTRUUS 85 



white scales, denser along the eye-margins, brown low on the 

 nape ; vertical bristles pale, those along the eye-margins black, 

 Mesonotum with dense narrow curved scales, brown and whit- 

 ish intermixed, general effect lustrous pale yellow with an in- 

 distinctly double median brown band that becomes faint poste- 

 riorly ; scutellum densely and continuously scaled with golden 

 yellow, the antescutellar space not paler. First abdominal seg- 

 ment with golden yellow scales and bristles, the rest black, with 

 rather narrow basal segmental white bands, widening on the 

 sides and minutely incised on the dorsal line, broken on the 

 last two segments ; venter white-scaled, with a median black 

 band, widening at apices of the segments ; traces of sublateral 

 subterminal patches. Wing-scales black, some patches of white 

 ones at base of costa, discal and sixth veins, and outwardly a 

 few of the outstanding ones on costa, first vein and upper edge 

 of cell near its apex ; outstanding scales numerous on upper 

 edge of cell and second vein, sparse on third vein and upper 

 fork of fourth, absent on fifth vein ; length of wing, 4.5 mm. 

 Legs black, the femora white beneath, knee-spots white ; tibise 

 and tarsi with many white scales intermixed, especially on the 

 under side ; tarsal claws toothed. 



Type, Cat. No. 30355, U. S. Nat. Mus. 



A captured female, Fallen Leaf, Lake Tahoe, California, 

 June 2, 1916, taken biting by day under pines by a meadow at 

 the north end of the lake by the sawmill. 



In other specimens the venter of the abdomen has the black 

 band crossed by transverse segmental subapical stripes. The 

 white scales of the wings are principally confined to the long 

 outstanding scales, the flat appressed scales being mostly black 

 except at the base of the wing. The dorsal abdominal bands 

 vary in the amount of incision, sometimes being broken on the 

 dorsal line, sometimes scarcely indented. 



This species is evidently of early occurrence and short lived. 

 It was the first species flying at the north end of Fallen Leaf 

 Lake (June 3) and was not taken after June 15. At Gold 

 Lake, in Sierra County, altitude, 6,700 feet, Prof. W. B. Herms 

 found ventrovittis on July 4, but two weeks later I was not 



