AKT. 23 TWO- WINGED DOLICHOPODID FLIES VAX DUZEE 27 



as long as the first two joints taken together, somewhat rounded at 

 tip; arista inserted above the tip, as long as the antenna. The 

 minute black orbital cilia descend about one-third of the eye height ; 

 beard yellowish-white, quite abundant. 



Dorsum of the thorax briglit green, with bronze reflections, the 

 posterior slope, a more or less distinct line each side of the acrostichal 

 bristles, and sometimes the scutellum more blue, or even violet; 

 acrostichal bristles very long posteriorly, in two distinct rows; 

 scutellum with two pairs of marginal bristles; in the best-preserved 

 specimen there is another small pair between the large median ones ; 

 dorsum of thorax v^dth considerable silvery white pollen, which 

 forms four stripes when viewed from in front. Dorsum of abdomen 

 black, wholly covered with silvery white j^ollen, except the first 

 segment; second and third segments with a large yellow spot on 

 each side, which leaves only narrow margins of black on anterior 

 and posterior edges and a narrow median line; fourth segment also 

 with yellow spots on the sides, but they are smaller and less distinct : 

 venter yellow, except on apical segments; hairs and bristles of the 

 abdomen wholly blacic, even on the venter. Hypopygium (fig. 23) 

 black, its appendages black, except the base of outer lamellae, two 

 small, pointed appendages back of the lamellae and the central 

 filament. 



Fore coxae blackish, still more or less yellowish, especially on 

 inner surface and toward the tip; they have long black hair on 

 anterior surface. Middle and hind coxae and their trochanters black. 

 All femora yellow; anterior pair more or less blackened on posterior 

 surface, and posterior pair black above for one-third of their length ; 

 fore femora with long black hair on the posterior surface; middle 

 ones with long black hair on the lower portion of both anterior and 

 posterior surfaces, leaving the lower edge glabrous. All tibiae yel- 

 low; posterior pair darkened toward their tips, which are narrowly 

 blackish. Fore and middlei tarsi yellow, darkened toward their tips, 

 especially the tips of the joints; fore tarsi with their joints as 

 38-13-9-6-9 ; middle ones as 45-21-14-8-7. Hind tarsi wholly deep 

 black, their joints as 33-32-20-12-8. Calypters yellow, with a nar- 

 row black border and long black cilia. Halteres yellow. 



Wings grayish, sometimes very slightly but uniformly tinged 

 with brown ; third vein bent backward a little at tip ; last section of 

 fourth vein bent near its middle, parallel with third at tip ; last sec- 

 tion of fifth vein twice as long as the crossvein. 



Female. — Face and front wide, covered with grayish-white pollen. 

 Third antennal joint about as long as wide ; arista subapical. Thorax 

 without or with but little blue color. Fore coxae yellow, with silvery 

 white pollen and long black hair on the anterior surface. Abdomen 

 green, with bronze reflections, sometimes more purple, covered with 



