cilia of tegular black ; wings unspotted, foimh longitudinal not broken ; 

 hind tibiffi tipped with brown; antennte black, red below on first jonit ] 

 fore coxae reddish in front ; fore legs plain ; vertex violet-bronzed. 



Ma/e.~Length 5 mm., length of wing 4.5 mm. Face and palpi 

 yellowish white. Antenn;>3 lengthened, the joints subequal in length, 

 black ; first joint reddish below, third with the arista preapical, a little 

 longer than antennae. Vertex violaceous with a cupreous tinge. Infra- 

 ocular cilia pale yellow. Dorsum of thorax and scutellum bronzed-green, 

 shining, not dusted. Abdomen strongly compressed, bronzed-green,' 

 shining, slightly dusted, incisures not well marked. Hypopygium not 

 large, lamella rounded apically, yellowish-tinged, narrowly black- 

 bordered, and fringed. Pleura dark green, dusted, yet shining in places ; 

 the place of the usual velvety-black antealar spot is taken by a Y-shaped 

 cupreous groove. Bases of middle and hind coxae and posterior face of 

 front coxae piceous, glaucous ; the anterior fiice of the front coxaj is dark 

 yellow, sharply limited, without the usual coating of black hairs, but with 

 three of the strong apical ones and a few pale hairs. Femora yellow, the 

 hind ones not ciliated and with a single anteapical bristle ; tibiis yel'low, 

 except the hind ones at tip on inner side, an elongate apical "dimple'' 

 and a narrow glabrous streak on the posterior face of hind tibiaj, the 

 dimple nearer the outside ; tarsi plain, blackened from tip of first joint 

 (hind ones missing in male) ; pulvilli whitish. Wings grayish-hyaline ; 

 veins not black ; fourth vein obtusely, but sharply, bent ; posterior cross- 

 vein distant less than twice its length from tip of fifth ; costa with a 

 small, lengthened, node-like swelling beyond junction with first vein. 

 Tegulse and halteres light yellow, the former with very long black cilia. 



The female diff'ers from the male by the broader, grayer face; greener 

 front ; shorter tegular cilia ; no costal node nor impression in hind'' tibia ; 

 front face of fore coxa3 with black hairs. Hind metatarsus with basal 

 two-thirds yellowish. 



One male and one female from Natrona Co., August 31, 1895, and 

 one female from Little Wind River, September 2, 1895, Wyoming ;' col- 

 lected by Ur. Wm. M. Wheeler. 



From the only species with which this could be confounded in any 

 way (sefosus, platyprosopus, prceustus, fulvipes and Coquilletti) this 

 species may be readily distinguished by the first short diagnosis. 

 3. Gymnopternus niirificus, n. sp. (Fig. 13.) 



Very similar to G. phyllophorus, Loevv, from which it diff'ers by the 



