May, 1920] Descriptions of Diptera 285 



Type locality, Katmai, Alaska, June, 1917 (J. S. Hine). 

 Type in collection of the Ohio State University ; paratype in 

 collection of the Ilhnois State Natural History Survey. 



Amaurosoma unispinosa sp. n. 



Female. Similar in color of head, thorax and abdomen to last 

 species, except that the black on orbits does not extend so far forward. 

 Legs and fore coxae entirely flavous. 



Cephalic characters, thoracic and abdominal chaetotaxy as in the 

 preceding species. Legs stout, fore femora stouter than mid and hind 

 pairs, armed with one bristle near base on anteroventral surface; mid 

 femur with one or two anteroventral bristles at middle, and five or six 

 along anterior surface; fore and mid tibiae as in preceding species; hind 

 tibia in type with two anterodorsal and two posterodorsal bristles. 



Length, 4.5 mm. 



Type locality, Katmai, Alaska, July, 1917 (J. S. Hine). 

 Type and paratype placed as in preceding species. 



Amaurosoma bispinosa sp. n. 



Female. Shining black, with distinct but not very dense gray 

 pruinescence, which is very faint on abdomen. Antennae black; frons 

 on anterior half golden yellow ; palpi pale yellowish testaceous ; proboscis 

 glossy black. Thorax glossy at bases of bristles. Legs yellowish tes- 

 taceous, femora browned apically, tarsi infuscated. Calyptrae and 

 halteres yellowish. Wings clear. 



Third antennal segment about twice as long as second, not acute at 

 apex above; arista tapered, microscopically pubescent. Presutural 

 acrostichals sparse, two-rowed; intra-alars very weak; prealar moder- 

 ately long; anterior stemopleural absent in type. Fore femur with two 

 strong bristles at middle on anteroventral surface ; mid femur with four 

 or five bristles on anterior and anteroventral surfaces; hind femur with 

 two weak anteroventral bristles at middle; hind tibia with two antero- 

 dorsal and two posterodorsal bristles. Last section of fourth vein about 

 three times as long as preceding section. 



Length, 5 mm. 



Type, Saldovia, Alaska, June 5, 1919. One female. 



Microprosopa Becker. 



There are three species of this genus in the collection all of 

 them apparently undescribed. 



Microprosopa arctica sp. n. 



Male and Female. Very closely resembling dissimilis in color, the 

 female differing only in having the anterior half of frons whitish 

 testaceous, the fore coxae almost entirely yellow, and the fine hairs on 

 thorax and abdomen pale. The male differs from that sex of several 



