514 



UNITED STATES NATIONAL MXISEUM BULLETIN 224 



nous. TegTila pubescent only; squama with multiple 

 fringe. 



Legs : Tlie legs rather densely appressed, short setate 

 dorsally and laterally; all the femora thickened, and 

 the anterior four femora more so than the hind pair. In 

 the type of genus the following complement of bristles 

 is present : on the hind femur 2 lateral near the middle, 



1 dorsolateral on the outer fifth, 1 apical and 1 subapical 

 dorsomedial bristle, 5 ventrolateral, and 5 or 6 ventro- 

 medial bristles. The hind tibia has 3 dorsal, 1 dor- 

 somedial, and 2 ventrolateral on the distal half. Middle 

 femur with a long, stout, anterior bristle just beyond the 

 middle and 3 anteroventral and 4 slender ventral bris- 

 tles on the basal half. This tibia bears 3 fine dorsal, 2 

 anterodorsal, and 2 long, stout, curved, oblique, antero- 

 ventral bristles, besides 2 posterior and 2 long, postero- 

 ventral bristles. Anterior femur with a ventral fringe 

 of 7 exceptionally long, slender bristles or bristly hairs 

 and some additional long pile ; its tibia has 1 dorsal at 

 the base, 2 post«rodorsal at the middle and beyond, and 



2 exceptionally long, rather slender posteroventral bris- 

 tles, 1 at the middle and 1 on the outer fourth. All tarsi 

 end in slender, sharp, apically curved claws, long pul- 

 villi, and moderately stout empodium. 



Wings: The marginal cell is closed with a rather 

 short stalk; subcostal cell narrow, the wing not ex- 

 panded anteriorly and only gently rippled. The an- 

 terior branch of the third vein ends very close to but 

 above the wing apex ; the posterior branch ends beyond 

 the wing apex a distance 3 or 4 times greater than the 

 distance of the anterior branch from the apex. First 

 posterior cell slightly narrowed in the middle; second 

 posterior cell only gently swollen anterobasally ; fourth 

 posterior cell closed and stalked, rather long, gently 

 convex anterioi'ly and distally. The lower end vein of 

 the discal cell is pulled far toward the base ; alula rather 

 large, the ambient vein complete ; the middle end vein of 

 the second basal cell is short. In Cerdistus anwnymus 

 the second posterior cell is very strongly widened an- 

 terobasally; in Cerdistus xanthocerus the anterior 

 branch of the third vein is strongly sigmoid and the 

 second submarginal cell is very gi-eatly widened at the 

 base. 



Abdomen : The abdomen is subcylindrical, rather 

 strongly tapered in the female, less so in the male. Pile 

 of the abdomen rather scanty, fine, setate and subap- 

 pressed, with a little longer stiff hairs laterally on the 

 first 2 or 3 tergites. First tergite with 2 or 3 pairs of 

 slender bristles, the lateral postmargins of second and 

 third tergites with 3 or 4 pairs of prominent bristles ; 

 remaining tergites with 1 or 2 such bristles. In the 

 male are seven tergites dorsally; the sixth is two-thirds 

 as long as the fifth ; the seventli a fourth as long as the 

 sixth and the eighth is visible only as a narrow lip 

 laterally in the type of genus. In Cerdistus xanthocerus 

 the seventh tergite is rather long, three-fourths as long 

 as the sixth, and the eighth dorsally is about one-sixth 

 as long as the seventh. Female with 7 tergites, the 

 seventh is tlu-ee-fourths as long as the sixth. Male 

 terminalia moderately large, not rotate; the dorsal 



proctiger elongate and tending to be rather strongly 

 arched outwardly, leaving a curled opening from the 

 dorsal aspect; aedeagus without prongs. Female ter- 

 minalia 'moderately elongate and quite strongly com- 

 pressed laterally on the eighth, ninth and to some ex- 

 tent on the tenth tergites; the eighth segment is coni- 

 cally expanded only quite near the base and dorsally ; 

 in Cerdistus pallidus the eighth segment is cylindrical. 

 First sternite without pile, the remainder with long, 

 slender hairs, or sometimes with weak, posterior bristles. 

 Verrall (1909) proposed the name PareVrzjm/s for sec- 

 tion B of Loew's original treatment of Itamus Loew. 

 Verrall separated these fi-om Neoitamus Osten Sacken 

 on the following characters : 



Face less naiTow with only the upper quarter 

 bare ; 



Upper occipital bristles not strongly proclinate 

 but gently curved, or nearly straight; 



Third antenna! segment but little tapering and 

 not thinned at apex as in Neoitamus ; 



Medial mesonotal stripes with tiny bristles; 



Male terminalia conspicuously large; 



Ovipositor composed only of eighth and remain- 

 ing segments but otherwise similar to Neoit- 

 arrvus. 

 I can not find that Verrall in his text associated any 

 certain species with Paritamus^ but in his list of species 

 of the Palaearctic region, given as an appendix, he 

 assigns here the following species : Paritamus genicu- 

 latus, glohifer. acanthodes, and inacrophthnlmus. En- 

 gel (1927, p. 98) associates Cerdistus geniculatus with 

 Paritamus Verrall without recognizing it. I therefore, 

 place Paritamus under Cerdistus Loew. The last three 

 species included by Verrall will now be found imder 

 MacMmus Loew, where they were assigned by Engel. 

 Distribution: Nearctic: Cerdistus albicomus Hine 

 (1909) ; auricomus Hine (1909) ; lepidus Hine (1909) ; 

 montanus Hine (1909) ; piceus Hine (1909) ; rubicun- 

 dus Hine (1909) ; wllUstoni Hine (1909) [=angusti- 

 frons Williston (1893) not Loew {AntiphHsson)^. 



Neotropical: Cerdistus anonym/as Williston (1901) ; 

 dolichomerus Williston (1901) ; humilis Bellardi 

 (1861) ; melanocerus Williston (1901) ; xanthocerus 

 Williston (1901). 



Palaearctic: Cerdistus alpinus Meigen (1820) 

 [=melanopus Meigen (1820)]; cervinus Loew (1856) 

 [ = cretaceus Becker (1913)]; delilis Becker (1923); 

 denticulatus Loew (1849) ; desertorum Efflatoun 

 (1934) ; dimidiata Macquart (1838) ; felegans Bigot 

 (1888) ; erythrurus Meigen (1820) [= dalmatinus 

 Strobl (1893), nigripes Strobl (1893), tenuis Macquart 

 (1834)], erythrurus alhispinus Palm (1876) ; -flavimy- 

 staceus Macquart (1849) [=albiseta Becker (1915)]; 

 flavipyga Becker (1923) ; geniculatus Meigen (1820) ; 

 heleni Efflatoun (1934) ; indifferens Becker (1923) ; 

 jubatus Becker (1923) ; junctus Becker (1923) ; lativen- 

 tris Pandelle (1905); manni Scliiner (1867); osiris 

 Wiedemami (1828) ; pallidus Efflatoun (1927) ; sarep- 

 tae Becker (1923); tenellus Becker (1923); zelleri 



