May, 1920] Descriptions of Diptera 277 



Hylemyia angustitarsis sp. n. 



Male. Black, shining. Thorax indistinctly vittate. Abdomen 

 with a black dorsocentral vitta which is broadened at anterior margin 

 of each tergite, where it merges with the fuscous anterior marginal 

 fascia; hypopygium glossy black, with slight grayish pruinescence. 

 Legs black. Wings very slightly brownish. Calyptrse and halteres 

 whitish yellow. 



Head rather small; narrowest part of frons not much wider than 

 anterior ocellus; parafacial at base of antenna not as wide as third 

 antennal segment, much narrowed below; cheek as high as width of 

 third antennal segment, with a series of long fine bristles on lower margin, 

 some of which, anteriorly, are upwardly curved; proboscis nonnal; 

 longest hairs on arista a little longer than its basal diameter; third 

 antennal segment narrow, about 1.5 as long as second. Dorsum 

 of thorax sparsely haired; presutural acrostichals of moderate, unequal 

 lengths, irregularly 2-rowed; prealar less than half as long as the bristle 

 behind it; steniopleurals 1:2; one or two bristly hairs adjacent to 

 stigmatal bristle. Abdomen narrow, depressed; hypopygium of moder- 

 ate size; fifth stemite with a few short, fine hairs along inner margins 

 and on inner half of each process and some long bristles on outer half. 

 Legs more slender than usual; fore tibia with a median posterior bristle, 

 the apical posterior one long, curved, blunt at apex; mid femur with some 

 long bristles on basal half of posteroventral surface; mid tibia with 

 usually one posterodorsal and one posteroventral bristle basad of middle ; 

 hind femur with a series of rather widely spaced bristles on antero- 

 ventral surface and two bristles at apex on posteroventral; hind tibia 

 with one or two weak bristles on both antero- and posteroventral 

 surfaces, four or five short anterodorsal and three posterodorsal bristles. 

 Costal thorn of moderate length; veins three and four very slightly 

 convergent apically; outer cross-vein straight. 



Length, 4.5-5 mm. 



Type, Katmai, Alaska, July, 1917. Paratypes, Katmai, 

 four specimens, August, 1917; Savonoski, Naknek Lake, 

 Alaska, seven specimens, July, 1919, one specimen, August 1, 

 1919. 



Hylemyia constrictor sp. n. 



Male. Black, subopaque, densely pale gray pruinescent. Orbits, 

 parafacials, face and cheeks with shining whitish pruinescence; antennge 

 and palpi black. Thorax indistinctly vittate. Abdomen with a 

 poorly defined broad fuscous dorsocentral vitta which is laterally 

 dilated at anterior and posterior margins of .each tergite; apices of fifth 

 stemite glossy black; hypopygium gray pruinescent. Legs black. 

 Wings clear, veins black, whitish at bases. Calyptras and halteres 

 whitish. 



Narrowest part of frons about twice as wide as width across posterior 

 ocelli; intcrfrontalia distinct on its entire length, with a pair of bristles 



