320 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



like, white, except at the root, which is brown ; they are angularly bei 

 in the middle, the latter half expanded, inverted-spoonshaped, yellow- 

 ish brown, bearing a fan-shaped tuft of long hairs at the end. Legs 

 metallic-coppery; tarsi black. Lobe at the end of the front tibiae very 

 large, deeply emarginate at the base; the long spine on the inner side 

 of the tibiae appears bifid, from a strong bristle near its tip ; middle 

 tibiae, besides some stiff bristles on the upper and under side, with a 

 fringe of soft hairs on the hind side, which become longer toward the 

 tip, and end there in a tuft of curly hair ; the hind tibiae end in a very 

 long curved spine, hook-shaped at the tip (if stretched out, it would be 

 nearly as long as one-third of the first joint of the hind tarsi) ; a smaller 

 spine near it. Wings yellowish at the root, otherwise tinged with brown, 

 especially between the first and third veins ; costal cell tinged with yel- 

 lowish ; a brown cloud on the great cross-vein ; another on the curva- 

 ture of the fourth vein ; some subhyaline spots near the root of the 

 wings, the most conspicuous of which on the proximal end of the third 

 posterior cell. 



Baft.— British Columbia (Crotch). A single male. 



Hydrophorus. 



Two species: one from Webber Lake, Sierra Nevada (July 25), is 

 allied to E. innotatus Loew from Sitka (Monogr., ii, p. 212) in the 

 coloring of the face, the upper part of which is greenish, and in other 

 characters ; its halteres, however, have a yellow, and not an infuscated 

 knob. The other species, taken near Santa Barbara (January 25), is 

 easily distinguished by the color of its first longitudinal vein, which is 

 brownish-yellow; the costa beyond the junction with the first vein is 

 of the same color. I abstain from describing these species, as my speci- 

 mens are not numerous enough nor well preserved enough for that pur- 

 pose. 



Medeterus breviseta Thomson (Eugenies Eesa, etc., 510) from Cali- 

 fornia is a Hydrophorus, as the author compares it to Medeterus litoreus 

 Fallen, which belongs to that genus. 



Psilopus. 



I found a single species abundant in Yosemite Valley about the begin- 

 ning of June. It is closely allied to Psilopus melampus Loew (Monogr., 

 ii, 253) from Mexico, but shows some differences, especially in the 

 structure of the legs. It would not be safe to describe it without the 

 comparison of specimens of P. melampus. 



Family EMPID^E. 



Is abundantly represented in California. I have nine species of Empis, 

 taken in Southern California in February and March ; in Marin and 

 Sonoma Counties in April and May; and about Webber Lake, Sierra 



