OSTEN SACKEN ON WESTERN DIPTERA. 249 



one or several species, it is useless to try to discover a difference between 

 them, I will only mention that Californian specimens frequently occur 

 which are larger and of a deeper brownish fulvous than any I have seen 

 from the Atlantic States. 



2. Bombylius albicapillus Loew, Centur., x, 42. — Not rare in Marin 

 and Sonoma Counties in April and May ; a specimen from Yosemite 

 Valley (June 13) has a whitish instead of yellowish fur. 



3. Bombylius metopium n. sp., <? .—Frontal triangle with a con- 

 spicuous covering of long, silvery- white, recumbent hair, entirely con- 

 cealing the ground-color ; face clothed with brownish-gray pollen, and 

 sparsely beset with long brownish-black pile ; a fringe of fulvous pile 

 along the oral margin ; long white pile on the under side of the head ; 

 occiput with pale yellowish pile ; occipital triangle black, with a few 

 black hairs ; antennae black, with black hairs on the first two joints ; 

 third joint but little expanded in its proximal part, about once and a 

 half the length of the two first taken together ; proboscis of moderate 

 length, about twice as long as the head. The far on the body is pale 

 yellowish, with some whitish reflections above the root of the wings ; a 



I stripe of dark hairs between the latter and the shoulders; chest with 

 I white pile; on the abdomen, rows of black hairs are visible on the 

 i posterior margins.of the segments ; on both sides of the second and the 

 ; following segments, they are more dense. Stem of halteres brownish; 



knob yellow. Femora black, beset with yellowish scales ; tibise and 

 j tarsi brownish-red, darker toward the tips. Wings brown at base and 

 I along the anterior margin, including the two basal, the marginal, and 

 1 the proximal half of the first submarginal cells ; on the inner surface of 

 i these cells, however, the brown is more diluted ; cross-veins at the base 



of the first and fourth posterior cells, as well as the bifurcation of the 

 | second and third veins, are clouded with dark brown ; the cross- vein 

 | at the base of the second posterior cell is about as long as the small 

 j cross- vein. Length 8-9 mm . 



Hob. — Lagunitas Creek, Marin County, California, April 19. Al- 

 | though I have but a single specimen, I do not hesitate to describe this 

 1 species, easily recognizable by the silvery tuft on the front of the male. 



4. Bombylius aurifer n. sp., $ 9 . — Male. — Epistoma with a dense 

 mystax of pale golden-3 T ellow hair, covering the edge of the mouth, 

 but not quite reaching the lower corner of the eye ; some few black 

 hairs in the upper part of this mystax near the orbit ; front clothed 

 with shorter hairs of the same color (but by far not as long and con- 

 spicuous as the snow-white pile on the front of B. metopium). Proboscis 

 a little more than twice the length of the head. The two first antennal 

 joints with black pile ; the third about once and a quarter the length of 

 the two first, rather broad, its greatest expansion beyond its middle; 

 rather suddenly attenuated at the tip. Under side of the head with 

 whitish pile; on the occiput, it is more yellowish-white. The fur of the 

 body rather uniformly pale yellow; a small tuft of black pile on each 



