ART. 10 TROPICAL AMERICAN DIPTERA VAN DUZEE 53 



Fore coxae yellow with two black bristles near the tip; middle and 

 hind coxae black with a large black bristle on outer surface, that on 

 middle ones near the base; femora and tibiae yellow; tarsi black, a 

 little yellowish at base; fore femora with two long bristles below 

 near the base and several small ones around them ; joints of fore tarsi 

 as 50-29-25-16-15; of middle ones as 85-47-34-1G-18 ; joints of hind 

 tarsi as 64^93-40-17-17. Calypters and halteres yellow, the former 

 with black cilia, these cilia not long or dense as in some species. 

 Pulvilli of fore tarsi very small, those on middle and hind tarsi 

 wholly wanting ; claws long and slender. 



Wings long and narrow, gray, more brownish in front; costa with 

 an enlargement at tip of first vein, which fills the costal cell at tip, 

 widening at proximal end so as to touch second vein at one point, but 

 this enlargement is only about twice as long as wide at its widest 

 part, the side toward second vein rounded ; last section of fourth vein 

 quite abruptly bent just before its middle, parallel with third at tip, 

 reaching the wing margin just before the apex of the wing; the 

 cross vein less than its length from the wing margin measured on 

 fifth vein ; third vein slightly bent back toward its tip. 



FefiuiJe. — Face as in the male in color and form, except that there 

 is a conspicuous transverse suture before the lower edge of the bronze 

 part and the yellow portion has no distinct depressions with a sharp 

 ridge between them as in the male; the lower edge is also rounded; 

 the antennae are sometimes almost wholly black; costa without an 

 enlargement ; fore femora without the long bristles below ; otherwise 

 about as in the male. 



Described from one male and four females, taken by J. M. Aldrich, 

 May 11, 1926, at El Jicara, Zacapa, Guatemala. 



fy^e.— Male, Cat. No. 41062, U.S.N.M. 



POLYMEDON NIGRICORNIS, new species 



Male. — Length, 4.5 mm. Face and front silvery white, face ex- 

 tending about twice its width below the eyes; palpi small, black, 

 rounded; antennae (fig. 62) black; first joint with hairs above; third 

 with a small yellowish spot below at base; proboscis black; lower 

 orbital cilia rather long, whitish, the black cilia descend to about 

 the middle of the eye. 



Thorax shining green with violet reflections, which extend upon 

 the base of the scutellum; a rather broad line of silvery white pollen 

 extends from the root of the wing to the front of the thorax ; pleurae 

 and coxae with silvery white pollen. Abdomen green with spots of 

 white pollen on the sides of the segments; hairs and bristles of the 

 thorax and abdomen black. Hypopygium black, upper surface more 

 yellow; its lamellae (figs. 63 and 64) somewhat triangular with a 



