176 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



PART 1 



tabling about 7 especially stout, long bristles. No 

 apical spine present; all tarsi end in long pulvilli, bas- 

 ally thickened empodium, and sharp claws. 



"Wings: The wings are of normal length, marginal 

 cell widely open; anterior branch of third vein ends 

 before the wing apex ; fourth posterior cell open ; but 

 slightly narrowed. Anal cell widely open ; second basal 

 cell ends in 3 veins ; alula large ; ambient vein complete. 



Abdomen : The abdomen is robust as far as the end of 

 the fourth tergite, as long as the wings. Pile of ab- 

 domen very scanty, quite short, fine setate except along 

 the sides of the first three tergites where it is long, 

 erect and fine ; bristles absent. First sternite reduced to 

 a narrow strip of chitin posteriorly, nearly but not 

 quite full width laterally. Sternal pile fine and long 

 on the basal sternites; absent on the first sternite. 

 Female with eight tergites, the eighth reduced to one- 

 third the length of the seventh. Female terminalia 

 with stout spines; lateral process with some fine, 

 spinous setae. 



Distribution: Palaearctic: Cycloscerus ptetycerus 

 Villeneuve (1913). 



Genus Holopogon Loew 



Fiqubes 127, 493, 1033, 1042 



Podoctria Megerle (Ms.), in Meigen, Systematise-he Beschrei- 



bung der . . . zweifliigligen Insekten, vol. 2, p. 279, 1820. 



Name without characterization. 

 Holopogon Loew, Linnaea entomologica, vol. 2, p. 473, 1847. 



Type of genus: Dasypogon nigripennis Meigen, 1820. 



Designated by Coquillett, 1910, the third of seven species. 

 Ccraturgus Rondani, not Wiedemann, Dipterologiae italicae 



prodromus, vol. 1, p. 156, 1856. 



Holopogon has 1 subgenus, Dasyholopogon Martin. 



Quite small flies characterized by the short face, the 

 generally divergent front with strong, numerous 

 bristles and rather long, loose pile. The mesonotum 

 is often high, giving these flies a hump-backed appear- 

 ance. They may be generally recognized by the hind 

 metatarsus, which is strongly enlarged, with the re- 

 maining segments decreasing in thickness; the corre- 

 sponding tibia is gradually swollen towards the apex. 

 In the type of genus the face is densely long, fine pilose 

 over the whole surface, the narrow ocular margins ex- 

 cepted, and with fine, bristly hairs over the oral margin. 

 In others the pile is greatly reduced and often replaced 

 by a few slender bristles. Length 4.5 to 9 mm. 



Head, lateral aspect : The face is short, gently convex 

 and z - etreating below the middle. The eye is equally 

 developed above and below, of moderate length and 

 strongly convex anteriorly, and gently convex posteri- 

 orly. Occiput moderately developed but shorter ven- 

 trally and dorsally; from a dorsal view the upper 

 posterior corners of the eye are broadly rounded and 

 anterolaterally recessive; in some instances this reces- 

 sion is quite marked. Pile of occiput scanty except on 

 the lower half, where it is longer and more abundant; 

 upper half with numerous, slender bristles which be- 

 come longer, a little stouter and distinct behind the 



vertex. The proboscis is short, subcylindrical and 

 obtuse, extending barely beyond the face and directed 

 either forward or obliquely downward; it bears fine, 

 short pile at the rounded obtuse apex. The base is not 

 swollen, the medial ridge absent and a narrow ventral 

 fissure present only on the basal fourth. Palpus of 

 two segments, each short and minute; first segment 

 excavated, second segment microporate with an apical 

 bristle. The antenna is attached just above the middle 

 of the head in profile; it is elongate and slender, the 

 first segment a little longer than the second, the second 

 slightly longer than high, dilated distally. The third 

 segment is a little more narrow than the second, widest 

 basally, tapering gently towards the apex and bearing 

 two microsegments ; the first microsegment is short, the 

 second thick but strongly attenuate, with a short apical, 

 bristly spine; these microsegments are usually held at 

 an oblique angle directed downward. Total length of 

 third segment iy 2 to 2 times as long as the combined 

 length of the first two segments. Pile of first and 

 second segments exceptionally long ventrally, composed 

 of very slender bristles or stiff, bristly pile; sometimes 

 the second segment in the middle below has a stout, 

 exceptionally long bristle. 



Head, anterior aspect: The face below antenna is 

 less than one-fourth the head width and divergent 

 below; the front is divergent to nearly one-third the 

 head width. Subepistomal area small, short, nearly 

 horizontal, concave and pubescent. Face densely pu- 

 bescent, in the type of genus with dense, long, bristly 

 pile from immediately below the antenna to the epis- 

 tomal margin, leaving only the sides narrowly apilose. 

 In many species the pile is greatly reduced and very 

 scanty on the upper half of the face, with or without 

 scattered bristles replacing the pile ; generally there are 

 a few, moderately stout bristles laterally along the 

 subepistoma. Front pubescent, distinctly divergent 

 and sometimes rather strongly widened, with abundant, 

 long pile laterally; the vertex is moderately excavated 

 and the high prominent ocellarium has vertical sides 

 carrying 2 or 3 pairs of long, slender hairs and some- 

 times shorter pile. Anterior ocellus set at the bottom 

 of the tubercle. Eye facets strongly enlarged centrally. 



Thorax: The thorax is pollinose. In many species 

 the mesonotum presents a rather distinctly hump- 

 backed appearance. Pile of mesonotum is rather loose 

 and scattered but long and fine and largely erect; in 

 some species it is replaced by scattered, bristly pile. 

 There may be a band of acrostical pile present or dorso- 

 central hairs differentiated, beginning near the suture. 

 In the type of genus the lateral bristles are extremely 

 weak, or absent, scarcely more than stiff hairs; there 

 are 1 or 2 on the notopleuron but on the supraalar 

 region and postalar region only stiff pile. Humerus 

 usually with long, delicate pile. In Holopogon dejec- 

 tus, pulcker, and violaceous, which are Neotropical 

 species, there are strong, stout, long, lateral bristles 

 consisting of 1 or 2 humeral, 2 or 3 notopleural, 1 or 2 

 postalar, and 3 to 6 scutellar bristles that are marginal. 

 Scutellum bare or micropubescent or with long pile; 



