OSTEN SACKEN ON WESTERN DIPTERA. 263 



parently belong here. The antennae are yellow, therefore paler than the 

 description makes them ; the sheath of the proboscis is variable in its 

 coloring, being sometimes entirely black, sometimes yellow, except the 

 lips, which remain black ; the costa is yellowish-brown (and not black, 

 as the description has it). The specimens from Illinois are smaller, and 

 have no stamp of a vein in the discal cell. These discrepancies not- 

 withstanding, I could not take my specimens for a different species be- 

 fore comparing thern with the types of the description. P. sulphurea is 

 figured in Mr. Glover's Manuscript Notes, etc. (Diptera, tab. v,f. 1). The 

 male of this species has the abdominal segments tinged with brownish 

 at the base, the hind margins remaining sulphur-yellow. 



2. Phthiria soolopax n. sp. — Drab-colored ; thorax with faint yel- 

 low lines; legs yellow, tips of -tarsi black; wings large, all the cross- 

 veins strongly, all the ends of longitudinal veins and the distal half of 

 the costa more faintly, clouded with brown ; proximal ends of the sec- 

 ond sub marginal and of the third posterior cells square, and both pro- 

 vided on the outside with a long stump of a vein. Length G-7 mm (with- 

 out the proboscis). 



Head yellowish ; cheeks, except the orbits, dark brown or reddish- 

 brown, shining, with a yellow cross-line in the middle; ocellar triangle 

 in the male dark brown, grayish-pruinose ; frontal triangle yellow in 

 the middle, reddish-brown on the sides, which color is separated by a 

 yellow line from the brown of the cheeks ; in the female, the interval 

 between the eyes is yellowish-brown, with a dark brown spot on the 

 vertex, upon which are the ocelli; the orbits of the eyes are sulphur- 

 yellow. Palpi long and slender, dark brown. Antennae yellowish- 

 brown, last joint more brown, nealy three times the length of the 

 two first taken together, its sides nearly parallel, its tip distinctly 

 emarginate. Proboscis nearly as long as the body in the male, some- 

 what shorter in the female. Thorax opaque yellowish-gray, beset with 

 an appressed golden tomentum ; on the dorsum, two pale yellow longi- 

 i tudinal lines, and a third, much more delicate one, between ; lateral 

 margins of the dorsum and antescutellar callosities likewise yellowish ; 

 scutellum with a yellow line in the middle, and often with a brown spot 

 on the tip. Halteres yellow, with a brown spot on the knob. Abdomen 

 brownish-yellow. Legs yellow, tarsi, except the base, dark brown. 

 Wings rather large and broad; the proximal ends of the second sub- 

 marginal and of the third posterior cells are square ; each emits on the 

 outside a long stump of a vein, projecting, the one into the first sub- 

 marginal, the other into the discal cells; the cross-veins at the base of 

 the second sub marginal and of the four posterior cells are clouded with, 

 dark brown, which clouds extend along the above-mentioned stumps; a 

 large cloud at the bifurcation of the second and third veins; the costal 

 margin, especially beyond the end of the auxiliary vein, and the ends of 

 ' all the longitudinal veins, are also clouded. In most specimens, there 

 | is a curved stump of a vein with a cloud upon it, on the second vein, 

 j opposite the small cross-vein, and inside of the first submarginal cell. 



