214 DIPTERA. 
To Bigot’s short description of this species I will add some particulars from a typical 
fernale specimen which the author has been kind enough to send me for examination. 
The front is as broad as the eyes; the frontal band scarcely differs in coloration from 
the lateral portions; the frontal bristles descend as far as the root of the antenne ; 
orbital bristles areabsent. The face is distinctly carinated ; the inferior portion of the 
cheeks equals two-thirds of the longitudinal diameter of the eyes; the vibrisse are at 
some distance above the oral margin. The antenne are inserted below a line drawn 
through the middle of the eyes. The abdomen, and also the scutellum, is densely 
armed with erect spines; on the hind margin of the scutellum are some long macro- 
cheetze ; the abdomen is broadly ovate. The legs are black, the tibia, however, some- 
what rufo-piceous; the bristles of the front femora are regularly arranged and form a 
row on the upper- and another on the underside, those of the underside being the 
longest ; the middle and hind femora have long and stout bristles on the underside ; 
the tibia have outwardly several bristles, those of the front pair being shorter than the 
others. The tegulz are dark brown, the wings grey ; the small cross-vein stands a little 
before the middle of the discal cell; the curvature of the fourth vein is angular, but not 
appendiculated, the apical cross-vein concave, the posterior cross-vein slightly curved. 
PROSENA. 
Prosena, St.-Fargeau & Serville, Encycl. Méth. x. p. 500 (1825). 
This genus, like the preceding (Hystrisiphona) is characterized by the long filiform 
proboscis, with small or rudimentary terminal lips, and by the plumose arista; it differs 
from Hystrisiphona by the normal macrochetz on the scutellum and abdomen. 
In the Central-American collections before me I find specimens of five species 
belonging to it, which may be distinguished as follows :— | 
1. Macrocheetze on the disc and on the hind margin of the abdo- 
minal segments . . . . . .s. - oe ee we 
Macrochetze only on the hind margin of the abdominal 
segments. . . . ©. «© «© 2. 6 . A, 
2. Abdomen and legs yellowish-rufous . . . . . . . . . Jacertosa, v. d. Wulp. vi" ha 
Abdomen and legs black or piceous . . . . ..... 38z 
3. Abdomen unicolorous black. . . . . . . .. . . .. valida, Br. & v. B. Pal 
Abdomen black, with cinereous or whitish reflecting spots . . tessellans, v. d. Wulp.2rse fn 
4. Cinereous species; foot-claws and pulvilli short in both sexes. curvirostris, Big. \y x 
Black species; foot-claws and pulvilli elongate in the male | 
SCX ew ee ee ew we. melena, v. dd. Wulp. bale 
Among the above-mentioned species there is but a single one, P. curvirostris, which 
shows all the generic characters of the common European form, P. siberita (Fabr.), i. ¢ 
having the foot-claws and pulvilli short in both sexes and only marginal macrochete on 
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