ART. 16. NORTH AMERICAN SCELLUS GREENE. 9". 



4. SCELLUS MONSTROSUS Osten Sacken. 



Plate 1, fig. 6 ; plate 2, figs. 13 and 20 ; plate 3, figs. 26 and 27. 

 tScellus nionstrosuH Osten Sacken, Western Diptei'a, 1877, p. 319. 



''''Male. — Thorax brownisli-graj', with several rows of brown dots 

 on which the bristles are inserted, and two approximate brown lines ; 

 wings tinged with brownish ; anal appendages of the male at least as 

 long as the abdomen, white; their end brownish-yellow, inverted 

 spoon-shaped. Length 6-7 mm. (without the appendages). 



'' Face brownish-ocher-yelloAV ; antennae black ; front dull greenish 

 gray; inferior orbit beset Avith yellow hair; the superior with stiff, 

 black spines. Ground color of the thorax concealed under a thick 

 grayish-brown pollen; three rows of brown dots, in linear groups 

 of three or four, bear the usual dorsal bristles ; on each side of the 

 intermediate row there is an uninterrupted brown line reaching to 

 the scutellum; the coppery ground color of the thorax is visible on 

 the dorsum above the wings; a large, coppery, shining spot on the 

 upper part of the pleurae ; a smaller one at the foot of the halteres ; 

 abdomen copper-colored; halteres yellow, the extreme root brown- 

 ish; tegulae with yellow cilia. Anal appendages at least as long as 

 the abdomen, ribbonlike, white, except at the root, which is brown; 

 they are angularly bent in the middle, the latter half expanded, in- 

 verted spoon-shaped yellowish-brown, bearing a fan-shaped tuft of 

 long hairs at the end. Legs metallic-coppery ; tarsi black. Lobe at 

 the end of the front tibiae very large, deeply emarginate at the base; 

 the long spine on the inner side of the tibiae appears bifid, from a 

 strong bristle near its tip; middle tibiae, besides some stiff bristles 

 on the upper and under side, with a fringe of soft hairs on the hind 

 side, which become longer toAvard the tip, and end there in a tuft of 

 curly hair; the hind tibiae end in a very long curved spine, hook- 

 shaped at the tip (if stretched out, it would be nearly as long as one- 

 third of the first joint of the hind tarsi) ; a smaller spine near it. 

 Wings yellowish at the root, otherwise tinged with brown, expecially 

 between the first and third veins; costal cell tinged with yellowish; 

 a brown cloud on the great cross- vein ; another on the curvature of 

 the fourth vein; some subhyaline spots near the root of the wings, 

 the most conspicuous of which is on the proximal end of the third 

 posterior cell." 



Habitat. — British Columbia (Crotch). A single male. 



Tyfe locality. — British Columbia (Crotch). 



Distrihution. — Tennessee Pass, Colorado, July 24, 1917, J. M. Aid- 

 rich, collector. Burns, Oregon, B. G. Thompson, collector. Lake 

 View, Montana, August 3, 1920, A. N. Caudell, collector. Yellow- 

 stone Park, Canyon Camp, August 12, 1918, A. L. Melander, col- 

 lector (A. L. M.). 



