OSTEN SACKEN ON WESTERN DIPTERA. 221 



thirds of first, more than one-half of second bascl cell dark brown ; the 

 dark brown cross-band does not reach the posterior margin, and does 

 not fill out the third, fourth, and fifth posterior cells; at the proximal 

 end of the fifth posterior cell, near the cross-vein, the«brown often but 

 not always shows a small hyaline space ; apical spot small, pale gray- 

 ish brown, occupying the extreme end of the marginal and first sub- 

 marginal, and encroaching but very little on the second submarginal 

 cell ; the hyaline triangle reaches the first longitudinal vein (if there is 

 any connection between the apical spot and. the cross-band, it is a very 

 faint one). Length 9-10 mm . 



Hob. — Webber Lake, Sierra County, California, July 20-27. Four 

 females. 



The eyes of this species in life are like figure 2 of my Prodrome (p. 

 369), the two central black spots being sometimes disconnected. 



This species is closely allied to C. nigripes Loew, and still more to 

 C, lapponicus Loew, but seems to be different from both, as in those 

 species the apical spot seems to be confluent with the cross-band (if I 

 understand Dr. Loew's expression, " der schmaleSpitzenfleck . . . . steht 

 rait der Schwarzung des Yorderrandes in vollstandigster Verbindung " — 

 Verb, zool.-bot. Ges., 1858, p. 623). C. nigripes occurs not only in Lap- 

 land, but, according to Loew, also in Sitka. 



2. Chrysops fulvaster n. sip.— Female. — Facial tubercles either 

 entirely red or red mixed with black; frontal tubercle comparatively 

 small, pale red, with a black upper margin more or less extended; 

 palpi pale reddish. Thorax clothed with a yellowish-brown pollen, 

 four stripes, leaving blackish intervals between them. Abdomen: — 

 two basal segments yellowish, the first with a transverse black spot 

 under the scutellum, the second with two black spots, separated by 

 a yellow interval in the middle ; the following segments black, with 

 yellow posterior margins, and a more or less distinct yellow longi- 

 tudinal line in the middle. Legs rufous, more or less black on the 

 joints ; front tarsi and the tips of the other tarsi black. Wings some- 

 what pale brown, almost grayish along the hind margin ; a hyaline 

 space occupies the end of the first basal cell, the larger portion of the 

 second basal, the whole anal cell except its distal end, and the proximal 

 half of the anal angle ; a crescent-shaped subhyaline space separates the 

 brown cross-band from the more grayish apex of the wing ; the inside 

 of the discal cell is paler brown, a spot in the fourth posterior cell sub- 

 hyaline. Length 6-7 mm . 



Male. — Black, except the face; palpi black; narrow lateral margins 

 of abdominal segments 1 and 2 and hind margins of the other seg- 

 ments yellow ; fulvous pollen in stripes on pleura and above the root 

 of the wings; fulvous pile on these stripes. Prevailing color of front 

 legs black; of the two hind pairs reddish. W r ings uniformly tinged 

 with black; a crescent shaped subhyaline space separates the usual 



