586 



UlSnTED STATES NATIONAL MUSEUM BULLETIN 2 24 



Rather large flies related to Cinadus Wulp, from 

 which they appear to be chiefly distinguished by the 

 small, tightly enclosed genital cavity of the male and 

 in the female by the presence on the eighth sternite of 

 an exaggerated, posterior fringe of long, spikelike 

 spines or spinous bristles. I can find no other basis for 

 distinction. Length 16 to 18 mm. 



Head, lateral aspect: The head is comparatively 

 short but large, the very large eye slightly flattened 

 anteriorly with a large area of enlarged facets. Up- 

 per half of the face plane with the eye, the lower half 

 slightly gibbous, a little more prominent because of the 

 recession of the eye. First antennal segment more than 

 tliree times as long as. wide; the second segment is IV2 

 times as long as wide, but bears short setae above, 

 longer setae and 1 or 2 weak bristles below. The third 

 segment is short, quite thin, oval with the base slightly 

 narrowed and the apex somewhat more narrowed. A 

 microsegment is absent, the style is long and slender 

 at least as long as the combined length of all three seg- 

 ments. Upper occipital bristles rectangularly procli- 

 nate; the middle of the gibbosity of the face bears a 

 vertical row on each side of 4 quite long, moderately 

 stout, black bristles, finely attenuate, and between these 

 a vertical row of 4 more bristles which are stout and 

 white. Along the sides of the subepistoma there are at 

 least 5 quite long, stout bristles, the upper element 

 white and 5 long, bristly hairs. 



Head, anterior aspect : The width of the head is about 

 114 times the height. Face below the antenna is nar- 

 row, about a ninth the head width and strongly 

 widened below. Front small, slightly wider than the 

 upper face with a double row of bristly hairs along the 

 eye margin. Vertex slightly narrowed opposite the 

 anteriorly placed ocellarium but widened posteriorly. 

 Tlie vertex is rather deeply excavated with nearly ver- 

 tical sides, the ocellar tubercle is small with vertical 

 sides and bears a pair of strongly curved and proclinate 

 bristles behind the ocelli. 



Thorax: The mesonotum is rather high, somewhat 

 narrowed anteriorly and bears scattered, suberect setae. 

 An irregular band of acrostical setae is continued the 

 full length of the mesonotum and long, slender dorso- 

 central bristles begin a little in front of the suture. 

 Humerus with fine, long, pile. Lateral bristles quite 

 long, moderately stout and attenuate. The notopleuron 

 bears 2 bristles, there is 1 stout supraalar, sometimes 

 followed by a more slender bristle above the postalar 

 callosity; postalar callosity with 1 long, stout and 1 

 weak bristle. There is a weak posthumeral bristle pres- 

 ent. Scutellum thick, convex, with distinctly impressed 

 rim, the posterior part of the disc with fine setae and 

 the margin with a pair of quite stout, long bristles. 

 Metanotal callosity creased behind and bearing bristly 

 pile. Pronotum with 4 widely spaced bristles. Post- 

 metacoxal area membranous but with the lateral meta- 

 sternum encroaching to some extent laterally. Proster- 

 num fused anterolaterally. Metapleuron with at most 

 extremely weak bristles or bristly hairs. Hypopleuron 

 with 1 long, slender, black bristle and a few hairs. 



Legs : The legs are similar to Cinadus. The bristles 

 on the ventral surface of the femora are emphasized on 

 the basal halves of all of the femora. 



Wings : The wings are similar to Cinadus. The mar- 

 ginal cell is quite wide apically, closed with a short 

 stalk. The posterior branch of the third vein has a 

 deep, conspicuous bend in the middle. Only the apical 

 third of the wing and the margin of the posterior cells 

 villose. Wing otlierwise like Chmdus. 



Abdomen : In the abdomen of the male the sides of 

 the first 5 segments bear conspicuously long, rather 

 stout, posterior bristles on the lateral third of the ter- 

 gites. Weaker bristles or bristly hairs are on the re- 

 maining tergites. Males with eight tergites, the eighth 

 is almost linear in the middle, a little longer laterally. 

 Females with seven tergites not included in the oviposi- 

 tor. Male termiiialia quite large and broad from the 

 dorsal aspect. The forceps are long, especially the pos- 

 terior two-thirds, which are slender and crossed api- 

 cally. Dorsal part with a long, blunt, conspicuous arm. 

 There is a strong gap between the gonopod and forceps. 

 The gonopods meet below and have claspers. Hypan- 

 drium short. Females with 3 or 4 bristles, which are 

 prominent on the posterior margins on each side of all 

 of the tergites. The ovipositor consists of the rather 

 small and somewhat compressed, triangular or sub- 

 conical, short, eighth segment and the still smaller and 

 more narrow ninth and tenth segments, which, together, 

 are as long or slightly longer than the eighth segment 

 and depressed downward. Second to fifth sternites with 

 some long, slender bristles; seventh sternite with a 

 posterior fringe of more stout, black bristles consisting 

 of 4 pairs. Posterior margin of the eighth sternite with 

 4 or 5 pairs of remarkably stout, long, spikelike bristles. 



Chaetogoiwphora chaetoprocta, new species 



Length 20 mm. Male, female. Head : The head is 

 black, except on the lower, gibbous portion of the face, 

 which is liglit brownish yellow. Occiput covered with 

 gi'eyish pollen, the vertex and front with light, brown- 

 ish yellow pollen, and the face everywhere with pale, 

 bi'ownish yellow micropubescence. Ocular margin of 

 the face on the upper half with a linear, vertical row 

 of longer, appressed micropubescence. Gibbosity of 

 face confined to the lower half, with numerous, long, 

 white bristles restricted to the central portion and con- 

 tinued down the sides of the subepistoma. On the up- 

 per part of the gibbosity are 4 to 6 long, slender, black 

 bristles and sometimes more slender, black elements 

 mixed with pale bristles along the sides of the subepis- 

 toma. Palpus slender, long, blackish with yellow hairs. 

 Proboscis black, tlie apex acute and narrowed above 

 and below. The antenna pale brownish yellow with the 

 small, elongate oval, apically tapered, third segment 

 brown and the long, slender style black. Pile of an- 

 tenna bristly and black. Front with chiefly black 

 bristles and a few, yellow elements along the sides. 

 Behind the ocelli several small, black bristles are curled 

 forward. Bristles of upper occiput black and pro- 

 clinate. 



