342 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. 



on a conical, black projection of the front ; joints nearly of the same 

 length, the first cylindrical, the second snbtriangalar, the third rounded, 

 somewhat brownish; arista yellowish. Face and front golden-yellow, the 

 former with a black stripe reaching from the antenuse to. the mouth ; 

 cheeks black; vertex black; posterior orbits golden-yellow. Thorax 

 black; humeri, two dorsal lines, interrupted in the middle and not reach- 

 ing the scutellum, a large spot on the pleurae and a smaller one under it 

 yellow ; scutellum yellow, its posterior edge black, beset with brownish 

 pile; halteres with yellowish knobs. Abdomen yellow; first segment 

 black at base ; the second segment has two narrow black cross-bands, the 

 one at the base, the other about the middle ; the second does not reach 

 the lateral margins : they are connected- in the middle by a black line ; 

 the third segment has a narrow black border anteriorly, a small, black, 

 diamond-shaped spot in the middle, and two black streaks on each side 

 between this spot and the lateral margin ; the black anterior margin of 

 the fourth segment is entirely concealed under the preceding segment, 

 but a diamond-shaped black spot in the middle and black streaks on the 

 sides are similar to those of the preceding segment ; hypopygium yel- 

 low. Femora black, except the tip, which is yellowish ; the hind femora 

 have the latter half brownish-yellow ; tibiae and tarsi brownish-yellow ; 

 the two last joints of the tarsi black ; the end of the third joint brown. 

 Wings tinged with brownish, somewhat yellowish at the base and along 

 the anterior margin ; a brownish cloud on the cross- veins. Length 



Hah. — Webber Lake, Sierra County, California, July 27. A single 

 male. 



This species is very like the well known Sphecomyia vittata, but is 

 smaller, has the two first joints of the antennfe much shorter, and a 

 Somewhat different picture of the third and fourth abdominal segments j 

 the femora are darker. In other respects, the resemblance is great. It 

 is not improbable that the female has a somewhat different abdominal 

 picture. 



Sphecomyia vittata has been brought from Southern Colorado by 

 Lieut. W. L. Carpenter. 



Ceria trtdens Loew, Centur,, x, 57. — A male from Sierra Nevada, 

 California (H. Edwards), agrees with the description, except that the 

 hind tarsi are yellowish at the base. 



Family MYOPID^. 



My Californian collection contains species of the genera Gonops, 3Iyopa, 

 and Zodion. 



MUSCID^ (in the widest sense). 



In this large division, I will confine myself for the present to the pub- 

 lication of a few species belonging to the Ortalidce and Trypetidce, the 

 two families so thoroughly worked up by Dr. Loew in the third volume 

 of the Monographs of the North American Diptera. To the small num- 



