48 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



KEY TO GENERA OF CHRYSOPOGONINI 



1. Anterior tibia without trace of spur or spine. Small or medium 



size flies with club-shaped abdomen, black with extensive, 

 lighter areas of golden pollen and the anterior half of the 

 wing brown in color like some Hymenoptera. 



Codula Macquart 



A well developed tibial spine present and accompanying 



basitarsal modification 2 



2. Third antennal segment bearing a spoon-shaped, semifused 



microsegment holding a short, stout spine. First posterior 

 cell open, or closed with a long stalk. 



Chhtsopogon Roeder 



Third antennal segment bearing a conical microsegment with 

 apical spine 3 



Female terminalia without spines and of the same elongate 

 construction as in Chrysopogon Roeder. Third antennal 

 segment wide, oval and large, a little swollen laterally; 

 apical segment and spine quite minute. 



Opseostlengis White 



Female terminalia with conspicuous spines; tibial spur and 

 notopleural spines present Chbtsedtria Hardy 



Genus Chrysopogon Roeder 



Figures 6, 7, 14, 400, 822, 831, 995, 1599, 1640, 1655, 1808, 1925, 

 1940, 1944, 1945 



Chrysopogon Roeder, Berliner Ent. Zeitschr., vol. 25, p. 213, 

 1881. Type of genus : Chrysopogon crabroniformis Roeder, 

 1881, by monotypy. 



Large, frequently bright colored and pollinose flies 

 ■with robust abdomen and elongate, slender antenna. 

 They are readily recognized by the stout tuberculate 

 spine on the notopleuron, the protibial spine, and the 

 absence of spines on the female acanthophorites. 

 Length 12 to 27 mm. 



Head, lateral aspect: The head is rather long, due 

 chiefly to the prominence of the face, the eye being 

 short. Face conspicuous and well developed, becoming 

 gradually more extensive below. The occiput is rela- 

 tively short and expanded only sublaterally from the 

 eye margin. Its pollen is confined to the outer margin, 

 the pile abundant, long, but coarse and bristly ; the pile 

 is even more dense dorsally, where it might be described 

 as quite weak bristles. Proboscis moderately long, 

 stout at the base, peculiar and characteristic because of 

 its arched, dorsal and concave, ventral surface and its 

 attenuate, pointed, dorsoventrally flattened apex. It 

 has an exceptionally strong, dorsal keel, which grows 

 higher and ends a short distance from the base. The 

 apex has coarse pile and beyond the middle of the ven- 

 tral margin there are 2 or 3 characteristic, long, diver- 

 gent bristles on either side; the base has straggly hairs. 

 Palpus large, of 2 segments, the end segment with angu- 

 lar attachment, conspicuous, open pore, and the first 

 segment hemicylindrical and excavated; both with 

 numerous bristles. Antenna attached at the upper 

 fourth of the head, elongate, slender, a little longer than 

 the head ; the first 2 segments are short, subequal ; the 

 third segment barely tapered, with large, short, spoon- 

 shaped microsegment, which bears a dorsally exposed 

 spine. 



Head, anterior aspect: Face wide; width below the 

 antenna at least one-third of the head width; diverges 

 slightly below the antenna. The face is partly bare or 

 uniformly densely pubescent. Face either without pile 

 or with numerous soft fine hairs throughout its length. 



Bristles of the face confined to the oral margin, numer- 

 ous and spread in 1 or 2 rows, or rarely with a partial 

 medial row of bristles. Subepistomal area nearly hori- 

 zontal and concave. Front short, pollinose, with bristly 

 pile dorsolaterally. Vertex very little excavated; the 

 large ocellarium has sloping sides and large ocelli, and 

 only bristly hairs are present. 



Thorax: The thorax is densely pollinose, with some 

 areas bare on mesonotum or pleuron or both. The mes- 

 onotum is long, comparatively low and gently arched. 

 The pile in the type of the genus is long, only laterally 

 on the humerus and on parts of the pleuron. The pile 

 of the acrostical and dorsocentral rows is quite minute. 

 There are a few scattered, long, fine hairs on the pos- 

 terior mesopleuron and weak numerous bristles on the 

 metapleuron ; propleuron with abundant long hairs, fine 

 or stiff and coarse. In some species the acrostical and 

 dorsocentral pile is long and bristly. Metanotal callos- 

 ity exceptionally convex and bullose, densely micro- 

 pubescent, sometimes with a few long hairs. Scutellum 

 flat, wrinkled, micropubescent, virtually without pile, 

 the margin with a row of fine vertical setae. 



Legs: The femora are elongate, bare, rather stout. 

 The hind femur is slightly dilated distally, its tibia more 

 so. Hind femur with short, stout bristles laterally, 6 

 in number, none at apex. Hind tibia with similar 

 bristles, 2 ventromedial near the base, 4 lateral, which 

 are stout, and 2 dorsomedial on the basal half; at the 

 apex the bristles are confined in the type of genus to the 

 ventral half where there is a cluster of 8 bristles. Mid- 

 dle femur with 2 short, stout bristles on the anterior 

 half and 2 posteriorly; its tibia has 9 post ero vent ral, 2 

 anterodorsal at the base, 4 anterior, and 3 ventral 

 bristles. Anterior femur has only one bristle in the 

 middle posteriorly, its tibia has 10 posteroventral, and 

 8 posterodorsal and 8 anterdorsal bristles. Apex of the 

 anterior tibia with a sharp, long, stout spur on a low 

 protuberance. Basitarsus with several, stout denticles 

 but with no elevation. The claws are only moderately 

 sharp, the pulvillus well developed, the empodium 

 swollen at base and also flattened. 



Wings : The wings are elongate, the marginal and all 

 of the posterior cells, except the first, widely open. 

 First posterior cell closed with a long stalk, anal cell 



