SYNOPSIS OF NORTH AMERICAN SYRPHID^. 41 



plenrffi bushy. Abdonieu rather broadly oval, shiuing black, with 

 abundant pile like that of the thorax. Tegulse light yellow. Legs black, 

 with yellow pile ; femora at the tip, base and tip of tibiae, and basal 

 joints of middle tarsi, yellow or luteous ; front and hind tarsi brownish 

 with more or less yellowish. Wings subhyaline with an indistinct 

 brownish spot near the middle ; veins of the basal part yellowish. 

 Thirteen specimens, Colorado. 



Chilosia occidentalis. (Plate III, figs. 1, la.) 



Chcilosia occidentalis Williston, Proc. Am. Phil. Soc, xx, 305. 

 Habitat. — California! 



S . Length, ll"^"^. Eyes thickly pilose ; frontal triangle black, with 

 black pile, somewhat swollen and with a central depression. Auten- 

 nte black, third joint somewhat brownish, nearly orbicular, small; 

 arista with scarcely perceptible pubescence. Face shining black; on 

 the sides with rather long, sparse, light-colored pile ; slightly concave 

 from base of antennae to tip of tubercle, shortly and deeply concave 

 below the latter; a well-marked groove on the side parallel to the 

 eye, running obliquely to the base of the antennae. Thorax deep 

 green-black, with blackish pile mixed with shorter lutescent. Scutel- 

 lum on its border with a row of longer hairs. Abdomen oval, not at 

 all slender, shining metallic green on the sides and fourth segment; 

 the first three segments mostly opaque black; pile reddish yellow, 

 rather long and abundant on the sides of the segments, nearly bare 

 in the middle. Legs black, with yellowish and black pile ; tibiae red- 

 dish at base and tip. Wings with a slight blackish tint, the veins 

 black. 



One specimen, California. 



Chilosia pallipes. (Plate III, fig. 5.) 



Chilosia paUipea Loew, Centur., iv, 70. 

 ? Chilosia tristis Loew, ibid., 71. 



Habitat. — White Mountains, Washington Territory, Oregon!, Cali- 

 fornia, District of Columbia (O. S.). 



9 . Length, 7 to 8°^". Shining metallic obscurely green. Front moder- 

 ately broad, shiuing, lightly pollinose on the sides below, with a slight 

 concavity in the middle above the base of the antennae; pile yellow. 

 Antennae ferruginous red, third joint rather small, rounded-ovate; arista 

 black, rather thickly and long pubescent. Face whitish pollinose across 

 below base of the antennae ; shining black, except on each side below, 

 there is a yellowish spot, sometimes smaller, at other times large and 

 extending from the eye to the oral margin. In profile the face is deeply 

 concave below the antennae, and the tubercle large and obtuse. Eyes 

 bare. Humeri light yellow ; pile of thoracic dorsum very short, yellow. 

 Scutellum at the tip, or most usually nearly wholly, brownish yellow, 

 the base black ; pile yellow, and with six black bristles on its border. 

 Abdomen wholly shining, not very oval; pile very short, on the disk ob- 



