220 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



This segment is reddish brown, with dense, conspicuous, 

 long, black, bristly pile dorsally, laterally, and still 

 longer and somewhat more bristly pile ventrally ; 2 or 

 3 of the ventral bristles are reddish. Second segment 

 is as long as the first and also bears numerous, black, 

 rather long, bristly hairs on all sides, which, however, 

 are somewhat shorter than those of the first segment and 

 there are fewer lateral elements and the hairs tend to 

 be directed downward and upward; also 1 or 2 of the 

 ventral elements are reddish. Third segment with 5 or 

 6 conspicuous, dorsal, black bristles; this segment is 

 quite black in color, slightly longer than the second seg- 

 ment and bears at the apex a short, downturned, bristle- 

 tipped, slender microsegment. The face is not very 

 high, a little shorter than the prominent, oblique, sub- 

 epistoma. On the lower half of the face there are 

 numerous, long, curved, stout, bright reddish bristles, 

 which tend to change to black apically. 



Thorax : Mesonotum quite black, except at the lateral 

 margin, the humerus, the postalar callosity and a small, 

 medial extension of the lateral stripe just behind the 

 humerus, which are all light reddish brown. These red- 

 dish areas are covered thinly with very fine, reddish 

 yellow micropubescence or pollen, and in some lights 

 there is a conspicuous stripe of red micropubescence 

 running down the dorsocentral bristle row the entire 

 length of the mesonotum. There is present a single, 

 acrostical row of long, bristly hairs. Also there are well 

 developed, long, slender, reddish, dorsocentral bristles 

 beginning just past the humerus; in front of these are 

 shorter hairs. Lateral bristles red; there are 3 noto- 

 pleural, 1 supraalar, 2 or 3 bristles on the postalar cal- 

 losity, and 3 pairs of slender, reddish bristles on the 

 scutellum. Scutellum thick and black with the margin 

 rounded. The pleuron is dark reddish brown except 

 for black on the upper third of the mesopleuron, the 

 whole of the propleuron and also a small, blackish spot 

 ventrally in the middle of the hypopleuron. The meta- 

 notum beneath the scutellum is black but the metanotal 

 callosity is red. Micropubescence of the upper meso- 

 pleuron red but over most of the middle pleuron it is 

 yellowish white. Prostemum dissociated. 



Legs : The legs are reddish brown with the tibiae and 

 tarsi of the anterior four legs yellow. The pile is 

 rather dense, coarse, bristly, appressed and black. 

 Bristles, where present, are pale red. Hind femur 

 with a small, red bristle at the apex ventrolaterally, 

 another at the apex dorsomedially. The ventral sur- 

 face of this femur bears a scattered fringe of long, 

 blackish, bristly hairs. Claws black, the pulvilli dark 

 brown. 



Wings : The wings are uniformly dark reddish sepia 

 brown, except at the end of the radial sector where 

 there is a small, diffuse spot, which is somewhat lighter 

 red. Entire wing is uniformly covered with dense, 

 dark villi. All posterior cells widely open, the fourth 

 posterior cell very slightly narrowed on the margin. 

 Anal cell closed with a short stalk. 



Abdomen : The abdomen is dark reddish brown, with 

 the basal margin of the first tergite black. Also, the 



lateral margins of most of the tergites are narrowly 

 darker in color. Stemites reddish brown with thin 

 pollen the same color. Pile of abdomen short, ap- 

 pressed, setate and black but becoming longer on the 

 sides of the sixth tergite and still longer on the seventh 

 and eighth tergites. The whole terminalia are dark 

 reddish brown with dense, long, blackish, bristly hairs 

 and slender bristles. A few of the terminal, longer 

 bristles are reddish and curve strongly toward the mid- 

 line and these arise from the lateral apex of the 

 gonopod. 



Type. Male, Mount Basil, North Haiti, 4700 ft., 

 Sept, 9, 1934, collected by Marston Bates. Type in the 

 Museum of Comparative Zoology. 



Cystoprosopa, new subgenus 



Type of subgenus : Cystoprosopa sepia, new species. 



Flies of medium size with comparatively slender, 

 elongate, subclavate abdomen. Related to Plesiomma 

 Macquart. The face is strongly inflated and swollen 

 and is comparatively high with a low, nearly transverse 

 subepistoma. Length 17 mm. 



Head, lateral aspect : The head is unusually long and 

 the face is prominent, strongly produced from above to 

 below and distinctly convex. The inflated face is com- 

 paratively high, with the subepistoma large but nearly 

 horizontal. The occiput is unusually tumid and swollen 

 both above and below. Ventrally it bears coarse, scat- 

 tered hairs and weak bristles in the middle, with some- 

 what stronger bristles on the upper third. The dorsal 

 bristles form a loose patch behind the upper eye corners. 

 Proboscis short, robust, narrowed at base, and bluntly 

 narrowed at apex, which is anterodorsally truncate. 

 The proboscis does not extend beyond the face. It has 

 a low, dorsal keel or ridge over the middle and the 

 ventral surface is somewhat curved and bears basally 

 some short, bristly hairs. The apex has a few fine hairs 

 above and below. Palpus composed of two segments, 

 the first segment is short, excavated, the second spindle- 

 shaped, with large, apical pore and several bristly hairs 

 attached around the middle of the segment, none at apex. 

 The antenna attached close to the plane of the vertex 

 at the upper sixth of the head. It is elongate, at least 

 as long as the head. The first segment is more than 

 twice as long as wide and slightly longer than the second 

 segment. It bears numerous, long setae dorsally and 

 laterally, and ventrally a number of slender bristles, 

 which are rather abundant. Second segment with setae 

 above and below, and two slender bristles apically. The 

 third segment is as long as the first two segments com- 

 bined, long oval and in the middle about twice as wide 

 as the second segment. On its dorsal surface are 15 or 

 20 short bristles or long setae and at the apex it has a 

 conspicuous, short, wide, spoon-shaped microsegment 

 with enclosed spine. 



Head, anterior aspect: The width of the head is 

 nearly twice the height, and wider below. The face 

 is wide and below the antenna approximately a third 

 the width of the head. It is very strongly widened 



