ART. 10 TROPICAL AMERICAN DIPTERA VAN DUZEE 25 



Fore coxae wholly yellow, middle ones largely black, posterior pair 

 yellow, blackened on outer surface; all femora and tibiae yellow; 

 posterior tibiae black at tip; hind femora with long hair above and 

 below; fore tibiae with a row of four bristles of increasing length 

 on upper anterior edge and three smaller ones on upper posterior 

 edge; middle tibiae with two irregular rows of bristles above and a 

 row of four below, which increase in length apically ; posterior tibiae 

 with two rows of about six long bristles above, between these is a 

 glabrous stripe, they have long bristly hair below, which is longer 

 apically; fore tarsi wholly yellow, middle ones more brown, even 

 at base, posterior pair wholly black; joints of fore tarsi as 50-16- 

 14-9-10; of middle ones as 62-35-27-13-13; joints of posterior pair 

 as 45-54^1-23-13. Halteres wholly yellow; calypters black with 

 long, dense, black cilia, which are bent backward at tips. 



Wings grayish, slightly tinged with brown in front; third vein 

 straight ; last section of fourth vein with a very slight bend beyond 

 its middle, it reaches the wing margin beyond the apex of the wing, 

 and as it runs straight from base to tip (except for the slight bend 

 near its apex) it is nearly uniformly divergent from third vein for 

 its entire length ; first vein reaches two-thirds the distance to the cross 

 vein, which is a little beyond the middle of the wing and at right 

 angles to fifth vein ; fifth vein only gently arched, its last section not 

 bent backward any more than the basal portion; cross vein as 33, 

 last section of fifth vein as 48; sixth vein distinct and quite strong, 

 but tapering and ends before the wing margin ; in front of the sixth 

 vein is "a fold in the wing which reaches the wing margin and when 

 viewed from the right direction it appears like a rather strong vein. 



Described from two males ; one, the type, was taken by C. T. Greene 

 on Barro Colorado Island, Canal Zone, April 16, 1926 ; the other was 

 collected by Mrs. Annie Trumbull Slosson at Biscayne Bay, Fla. 

 She sent this specimen many years ago to J. M. Aldrich, in whose 

 collection it remained, marked " New Genus." 



Type.— Male, Cat. No. 41038, U.S.N.M. 



Genus SYMPYCNUS Loew 



Sympycnus Loew, Neue Beitr., vol. 5, 1857, p. 42; Mon. North Amer. Dip- 

 tera, pt. 2, 1864, p. 185, table of species. — Wheeler, Proc. Calilornia Acad. 

 Sci., vol. 2, 1899, p. 47, table of species. 



SYMPYCNUS IMPERFECTUS, new species 



Male. — Length 3.7 mm. Face very narrow, of nearly equal width, 

 silvery white. Palpi and proboscis black, the former with white 

 pollen. Antennae black, third joint small, about as long as wide, 

 somewhat triangular, obtusely pointed at tip. Lateral and inferior 

 orbital cilia long, white. 



