AMERICAN DIPTERA. 299 



pile. Legs wholly black, all the bristles and pile of the tibise and tarsi 

 and of the apical third of the femora black ; the pile of the rest of the 

 femora sordid white; femora slightly grayish pruinose. Wings grayish 

 hyaline, veins blackish, the transverse median vein a little further 

 removed from the base of the discal cell than from the apex. 



Type. — M. C. Z. A single female in the Loew collection is 

 probably the type. There are, in addition, four male and 

 three female specimens in Osten Sacken's collection, which are 

 probably those which he mentions in Western Diptera. 



Habitat. — California (type) ; near San Francisco, March 28, 

 (Osten Sacken) ; Los Angeles County, Cal. (Coquillett) ; Mount 

 Hood, Oregon (June 9). 



This species and tetragrammus are similar in the coloration 

 of the abdomen but markedly different in the stripes of the 

 dorsum of the thorax. 



Lasiopogon opaculus (PI. IX, fig. 6; PI. IV, fig. 8). 



Lasiopogon opaculus Loew, Berl. Ent. Zeitsch., XVIII, 367, 1874. 



9- — Length 8-9 mm. — Black; thoracic stripes obsolete; terminal 

 segment of abdomen polished black and black pilose; rest of the body 

 wholly obscured by a grayish-brown bloom, but the anterior angles of 

 the several abdominal segments broadly brownish. 



Translation. Ground color of body is, without exception, black; 

 head, thorax and abdomen with a denser dull bloom, but the last 

 abdominal segment wholly without bloom and polished black. The 

 bloom of the head and thorax yellowish-gray, almost brownish-gray; 

 distinct thoracic stripes are not perceptible on the specimen described, 

 yet the space between the middle and the lateral stripes appears 

 darker than the surrounding color usually is. The abdomen, except- 

 ing the last segment, is covered with a grayer bloom and entirely dull ; 

 from the second segment on, the anterior angles of the several seg- 

 ments are broadly brownish, which color is first on the fifth segment 

 less in degree, on the sixth segment somewhat broadened on the fore 

 part, likewise not very dense and gradually shades off into the gray, 

 so that it is indistinctly defined, whereas it has a sharp distinctive 

 limit on the preceding segments, which one distinctly notices when 

 one looks at the abdomen from behind. Halteres yellowish. Wings 

 grayish, venation normal; veins brownish-black; the anterior cross- 

 vein is considerably before the middle of the discal cell. The hair 

 and bristles are as usual in this genus; mystax, hair of the first two 

 antennas segments, of the front and of the upper part of the occiput 

 black; the hair on the larger lower half of the occiput, on the mentum 

 and on the under side of the proboscis white ; that on the lateral bor- 

 ders of the mouth opening pale yellowish. Prothorax with more 



TRANS. AM. ENT. SOC, XXXV. AUGUST, 1909 



