52 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 74 



coxae, legs, and feet colored as in the male; cilia of the calypters 

 black; venation about as in the male. 



Type. — Male, taken by W. A. Kellerman, in Guatemala; allotype^ 

 female, taken by Nathan Banks, July 15, 1924, at Barro Colorado 

 Island, Panama Canal Zone ; both the above in the Museum of Com- 

 parative Zo61og3^ A parafype in the United States National Mu- 

 seum was taken by C. M. Rouillard. at La Providencia, Siquinala^ 

 Guatemala. 



Paratype.—M^il^, Cat. No. 41061, U.S.N.M. 



Genus POLYM'EDON Osten Sacken 



Polymedon Osten Sacken, Bull. U. S. Geological and Geographical Survey 

 of the Territories, vol. 3, 1877, p. 317. — Aldrich, Trans. Ent. Soc. London, 

 1896, p. 318; Biologia, Diptera, vol. 1, 1902, p. 333, tables of species. — 

 Van Duzee, Annals Ent. Soc. Amer., vol. 20, 1927, p. 123, table of species. 



POLYMEDON TRANSVERSUS. new species 



Male. — Length 6 mm. ; of wing the same. Face wide, flat, extend- 

 ing as far below the eyes as its width at half its length, where it is 

 slightly narrowed; it is of a dark-bronze color clown to above the 

 lower margin of the eyes, where this color abruptly ends, the lower 

 part being yellow and having a sharp median carina, the lateral edges 

 also projecting forward so as to leave two broad, flat longitudinal 

 depressions, the yellow portion tapering downward, but cut off 

 straight at tip, not at all pointed ; the pollen of the upper portion is 

 arranged in transverse waves. Palpi large, somewhat round, yellow, 

 covered with white pollen, with a stout black spine at the middle of 

 lower edge and several delicate hairs. Front shining violet, this 

 color extending over the vertex in the middle; occiput green with 

 white pollen. Antennae black, lower edge of all joints a little yel- 

 lowish, first joint hairy above, about one and a half times as long as 

 wide, third joint rounded with the arista inserted above near the apex. 

 About six of the upper orbital cilia on each side black, the lower 

 cilia and the beard yellowish white and long. 



Thorax blackish with purple reflections, its pollen gray, mostly 

 confined to the anterior edge ; acrostichal bristles and presutural clor- 

 socentrals small, the former in two rows ; pleurae and coxae covered 

 with silvery white pollen. Abdomen green with black hair, white 

 pollen on the sides abundant. Hypopygium (fig. 61) short and stout, 

 greenish, its outer lamellae large, yellow, nearly round with short 

 delicate yellow hair ; there are also a pair of slender inner appendages 

 and a pair of thin, somewhat triangular, shining black lateral ap- 

 pendages projecting downward; the central organ is rather stout, 

 curved, reddish yellow, its sheath black, attached at the base of 

 the hypopygium and scarcely reaching the tip. 



