458 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



is more or less bare. The pile of tlie mesonotum is 

 scanty and composed of very short, quite stout, basally 

 thickened, suberect setae ; there is a double to quadruple 

 row of acrostical setae present, followed by a bare stripe. 

 Dorsocentral elements are poorly differentiated an- 

 teriorly, as short as the remaining setae until opposite 

 the postalar where there are 3 or 4 pairs of quite long 

 bristles. Himierus with 2 stout bristles. The lateral 

 bristles are quite long and stout, consisting of 2 noto- 

 pleural, 1 supraalar, 1 suprapostalar, 2 or 3 postalar, 

 and 1 pair of scutellar bristles. Scutellum thick, con- 

 vex, pollinose with impressed rim and scattered, long, 

 fine, erect pile. Propleuron with dense, long pile, the 

 pronotum with i pairs of stout, long bristles. Upper 

 mesopleuron with a patch of short, stout setae. An- 

 terior extension with only a few long, fine hairs ; the 

 posterior mesopleuron, upper sternopleuron, the ptero- 

 pleuron, and the anterior and posterior hypoplem'on 

 each have a patch of fine, erect, scattered pile, and a 

 patch spot of pubescence is present. Metapleuron with 

 a vertical row of 6 or 7 long, quite stout bristles. Meta- 

 notal slopes micropubescent only; metasternal slopes 

 and the metasternum with a few, long, fine hairs ; post- 

 metacoxal area membranous; postei'ior basalare with 3 

 or 4 short bristles. Prosternum dissociated. 



Legs : The middle and hind femora and their tibiae 

 elongate and relatively slender; the anterior femur is a 

 little thickened towards the base ; the pile is stiff but flat 

 appressed and setate; the bristles are rather stout but 

 only of moderate length except at the apices of the tarsi, 

 where they are exceptionally long. The hind femur 

 beare at the apex 1 dorsomedial, 2 lateral and back 

 from the apex 1 dorsomedial, and 1 dorsolateral bristle. 

 There are 4 lateral, 12 ventral, 8 or 9 medial bristles. 

 The hind tibia bears 4 or 5 dorsal, 4 lateral, 3 especially 

 prominent ventral bristles on the outer half. The brush 

 of setae extends nearly to the base and onto the first two 

 tarsal segments and apices of others. Hind basitarsus 

 elongate, as long as the next three segments. Hind coxa 

 with 2 lateral and 3 ventral bristles; middle coxa with 

 6 lateral bristles and 10 to 12 anterior bristles ; anterior 

 coxa with 10 or more anterior bristles. Middle femur 

 with 8 or more posterior, 5 or 6 ventral, 4 or 5 antero- 

 ventral bristles; its tibia has 2 posterodorsal, 1 dorsal, 

 4 posterior, 1 to 2 posteroventral and 2 long, stout, ven- 

 tral bristles at the middle and beyond. Apex with 6 

 bristles. Anterior femur with 2 bristles anteriorly at 

 apex and some 5 weak, slender, ventral bristles; its 

 tibia has 2 basal, anterior bristles, 5 dorsal and 3 excep- 

 tionally stout posteroventral bristles; the bristle lying 

 at the apical fourth is longer than the basitarsus. These 

 tarsal bristles are exceptionally long and stout. All 

 tarsi end in very long, slender, sharp claws, long slender 

 pulvilli, and long, stout empodium. 



Wings : The wings are exceptionally slender, hyaline. 

 The subcostal cell is extremely narrow; marginal cell 

 closed but with extremely short stalk or closed at the 

 margin. The first submargmal cell is unusually long 

 and takes origin before the end of the discal cell. The 



anterior branch of the third vein ends before the whig 

 apex, the posterior branch ends far behind the wing 

 apex. Three submarginal cells are present due to a 

 rectangular crossvein near the base of the first submar- 

 ginal cell. First posterior cell long and slender, the 

 fourth closed and stalked and anteriorly convex. Sec- 

 ond basal cell ends in 2 veins; anal cell closed; alula 

 present, ambient vein complete. 



Abdomen : The abdomen is considerably longer than 

 the wing ; at the base nearly as wide as the mesonotum 

 but rather rapidly tapered; the terminal portion is 

 much more narrow, the whole abdomen subcylindrical 

 and the first tergite laterally swollen. The pile is mi- 

 nute, fine, flat appressed and setate. The sternites have 

 long, fine pile on the basal segments. Lateral bristles 

 are present as follows: 5 or 6 on the first tergite, 2 

 laterally in the middle on the second tergite and the 

 remaining tergites with 2 to 4 stout, long bristles sub- 

 postmarginally on the lateral portion of the segment. 

 Male with eight tergites, the female with seven, those 

 tergites beyond lying in the ovipositor. Male terminalia 

 large, elongate, not rotate. The superior forceps quite 

 large and long and tend to enclose the cavity above and 

 below. Gonopod quite short, basal and ventral. The 

 proctiger is large and lies on the surface of the forceps 

 dorsally. Hypandrium well developed. In the female 

 terminalia the eighth segment is exceptionally long 

 and cylindrical or slightly depressed; ninth segment 

 also cylindrical and quite short. The tenth is depressed 

 and bears short, small, dorsal spines and at the apex 2 

 conspicuous, spikelike spines. Ninth sternite greatly 

 produced posteriorly as a flat, posteriorly notched plate ; 

 it has a wide, medial, longitudinal, ventral furrow. 



This genus is a dominant element in South Africa 

 where it apparently fills a niche similar to Proc- 

 tacanthus Macquart in North America and Satanas 

 Jacobson in central Asia. All of these three are rather 

 similar in construction and size. Alchnns occasionally 

 fomid in Asia. 



Distribution: Palaearctic: Alclmus ponticus Bigot 

 (1880) . Ethiopian : Alciinus aethlopicus Bigot (1891) ; 

 alamanus Walker (1849) [ = perlongus Walker 

 (1851)]; angustipennis Loew (1858); iiseriatus Cur- 

 ran (1927) ; 'brevipennis Ricardo (1922) ; cutKbertsoni 

 Hobby (1934) ; dons Curran (1927) ; frateimus Wiede- 

 maixn (1819) ; limbatus Macquart (1838) ; longurio 

 Loew (1858) ; ludens Wiedemann (1828) ; niimus Wie- 

 demann (1828) ; nigrescens Ricardo (1922) ; nigropal- 

 pus Hobby (1934) ; ruhicundus Hobby (1934) ; rubigi- 

 nosxis Gerstaecker (1871) ; setifemoratus Hobby 

 (1934); stenurus Loew (1858); taeniopus Rondani 

 (1873) ; tigns Karsch (1887) ; tristrigatus Loew 

 (1858). 



Oriental: Alciimis hospes Wiedemann (1819). 



Country unknown: Alchnvs longipes Macquart 

 (1838) ; sericans Wiedemann (1828). 



Refer to Ricardo (1921) for suggested additional 

 synonymy. See addendum (p. 595). 



