10 PROCEEDINGS OF THE NATIONAL, MUSEUM, vol. C5. 



5. SCELLUS VIGIL Osten Sacken. 



Plate 1, fig. 2 ; plate 2, figs. 10 and 23 ; plate 3, fig. 30. 

 Scellus vigil Osten Sacken, Western Diptera, 1877, p. 318. 



" Male. — Thorax grayish above, with two approximate brown 

 lines ; abdomen and pleurae copper-colored, partly metallic-greenish ; 

 wings subhyaline, with a double grayish spot on the great cross- 

 vein, and a similar larger spot on the last section of the fourth 

 vein; anal appendages of the male narrow, white, blackish at the 

 base. Length 3.5-4.5 mm. 



" Face brownish-yellow, narrow above, broader below ; antennae 

 black; the ground-color of the front is concealed under a grayish 

 pollen. Thorax above with a dense gray pollen almost concealing 

 the coppery ground color ; two approximate brown lines in its middle 

 stop some distance before reaching the scutellum ; between their end 

 and the scutellum, an opaque dark brown spot. Pleurae coppery, 

 with greenish reflection, slightly pruinose. The scutellum, with two 

 bristles, is greenish, coppery, or purplish. Abdomen (very much 

 shrunken and withdrawn in my specimens) coppery, pruinose above, 

 brilliant coppery, and greenish on the sides. Anal appendages 

 ribbonlike, white, blackish near the root. Legs metallic-green or 

 coppery, with purple reflections; tarsi black. The structure of the 

 legs agrees in the main with the description of the legs of S. filifer 

 Loew.^ Halteres whitish. Wings subhyaline, their root yellowish; 

 costa yellowish-brown before its junction with the first vein; a 

 double grayish spot on the great cross-vein, and a similar larger 

 spot on the last section of the fourth vein ; the latter is well defined 

 on the proximal and evanescent on the distal side." 



Hahitat. — ^Webber Lake, Sierra Nevada, July 22-24. Three males 

 found resting on stones on hillsides. 



This species differs from 8. filifer Loew (Fort Resolution, Hud- 

 son Bay Territory) in the coloring of the wings, which have no 

 longitudinal gray streaks between the veins, the color of the anal 

 appendages, which are not yellow at the end, etc. Nevertheless, the 

 resemblance between the two species must be very great. 



Tijpe locality. — Webber Lake, Sierra Nevada. 



Distribution. — Pullman, Washington, May 25, 1908. Moscow 

 Mountain, Idaho, June 17, 1918, July 5, 1919, July 9, 1920 (A. L. M.) . 

 Moscow, Idaho, no date. Pullman, Washington, May 31, 1913. 



6. SCELLUS AMPLUS Curran. 



Plate 1, fig. 3 ; plate 2, figs. 11 and 21. 



Scellus amplus Curban, Can. Ent., vol. 55, 1923, p. 73. 



" Middle tibiae swollen and polished at apex, with a long spme 

 just before the swelling beneath ; front basitarsus with a long spine 



8 Monograph, pt. 2, p. 210. 



