CHRYSOTUS. IT 9 



eyes are separated by the face, which is comparatively broad for a 

 male ; the face has a rather distinctly impressed middle line, is of 

 a metallic-green color, but opaque on account of the cover of 

 whitish dust. Palpi black, their whitish powder only becomes 

 visible when seen in a very oblique direction. Antennas black, of 

 middle size, their third joint is somewhat longer than in most of 

 the other species, hairy, and of a somewhat irregular form, because 

 that part, where the arista is inserted, is somewhat produced in 

 the shape of a lobe. Front metallic-green, dull on account of 

 brownish-yellow dust. Coxae and femora black, the latter with a 

 green metallic lustre ; the second joint of the fore coxae, the tips 

 of all the femora, all the tibiae and all the tarsi as far as the tip 

 of the first joint, yellow, the end of the feet brownish-black. Hairs 

 and bristles upon the feet very short, the bristles also very few in 

 number. Pulvilli of the fore tarsi rather small. Cilia of the 

 tegulae black. Wings somewhat grayish, with a rather protruding 

 anal angle ; the costa shows no thickening ; the last segment of 

 the fourth longitudinal vein is scarcely a little inflected, parallel 

 with the third and ends immediately before the extreme tip of the 

 wing. 



Hab. Illinois. (Le Baron.) 



Observation. — It is not necessary, when identifying this species, 

 to pay too much attention to the shape of the third joint of the 

 antennae, as it sometimes changes its form, especially when recently 

 developed specimens dry up. The separated eyes, the black cilia 

 of the tegulae, the color of the feet, and the costa without a thick- 

 ening, are characters which prevent its being confounded with any 

 other species known to me. 



2. Cilia of the tegulae pale. 

 a. Costa of the male thickened. 

 7. C. COStalis Loew. % and £. — Viridis, polline confertissimo ex 

 fusco cinereo opacus, femoribus nigris, genibus tibiisque flavis, maris 

 oculis distantibus et media costae parte valde incrassata. 

 Green, opaque on account of a very thick brownish-gray dust ; femora black ; 

 knees and tibiae yellow ; the eyes not contiguous in the male and the 

 middle of the costa thickened. Long. corp. 0.09 — 0.10. Long. al. 0.09. 

 Syn. Chrysotus costalis Loew, Neue Beitr. VIII, 64, 5. 



Male. Ground-color metallic-green, or blue-green, but so 

 thickly covered with brown-gray dust as to conceal this color. 



