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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



bear some slender, ventral bristles towards the base. 

 The middle, tibia lias better developed bristles, all of 

 which are long and slender, as follows: 4 posterior, 4 or 

 5 posteroventral, 4 or 5 anteroventral, and 2 or 3 ante- 

 rior. Claws fine and sharp; pul villi well developed; 

 the ompodium slender and short. 



Winfjs: The wings are exceptionally broad in the 

 majority of species, occasionally slender, as in IIolco- 

 cephala calva. The marginal and all of the posterior 

 cells are widely open, the anal cell closed and with a 

 long or short stalk. Middle end vein of the second 

 basal cell exceptionally long. Alula moderately devel- 

 oped; ambient vein complete. Typically, the wings in 

 most species are strongly tinged with brown, particu- 

 larly towards the base. 



Abdomen: The abdomen is short and comparatively 

 broad, sometimes pedicellate; the surface of the tergites 

 is quite soft, so that it often presents on drying a wrin- 

 kled appearance. Seven tergites are present and well 

 developed in the male; the second tergito nearly as long 

 as the last four and each tergite becomes progressively 

 shorter, so that the apex of the abdomen is considerably 

 narrowed except in petiolate species like Ilolcocepliala 

 calva. Females with 8 well developed tergites. Abdo- 

 men densely pollinose with very scanty, short, incon- 

 spicuous pile along the sides. Sides of the first tergite 

 with a few bristly hairs. Male terminalia large, con- 

 spicuous, not rotate, and open below. The aedeagus is 

 long, conspicuous, arched and trifid at the apex; it is 

 often carried ventrally at some distance below the 

 remainder of the terminalia. The proctiger is unusu- 

 ally largo and tubular or hemicylindroid. The epan- 

 drium is short, broad, with a deep lint wide triangular 

 cleft which does not reach to the base; this structure is 

 finely micropubescent. or pollinose as are the preceding 

 tergites and it has a small, narrow, lateral part which 

 may he turned downward. The gonopod is elongate, 

 polished, apt. to bo pointed apically and tends f o enclose 

 the lower edge of the proctiger. The hypandrium is of 

 moderate length, pollinose on the basal half, polished 

 distally, and emits on each side dorsally, near the base 

 of the gonopod, a long, slender prong, which seems to 

 ariso from beneath the edge of the hypandrium; this 

 prong possibly represents the same structure which in 

 the Asilinae we have designated as the clasper. The 

 aedeagus arises between these prongs. Female termi- 

 nalia small, inconspicuous, without apical spines. 



These quaint, little flies, (he gnat-ogres, are fre- 

 quently abundant, in swampy areas where they are 

 found on the tips of twigs and leaves among rank 

 undergrowth. 



Distribution: Nearcfic: Holcocephala abdominalis 

 Say (1823) [ = aeta Walker (1849), laticeps Wulp 

 (18G9), rufiventris Macquart (1838)] ; amastris Walker 

 (1849) ; calva Locw (1872) ; fusca Bromley (1951). 



Neotropical: Ilolcocepliala affinis Bellardi (1861); 

 alboatra Walker (1851); apicalis Walker (1854); 

 fcoriacca Wiedemann (1821); deltoulea Bellardi 

 (1861); dimidiate Hermann (1926); divisa Walker 

 (I860) [ = longipennis Bellardi (1861)] ; jemorata Her- 



mann (1926); ftmbriata Hermann (1926); inornata 

 Rondani (1848); luteipes Hermann (1926); macula 

 Itondani (1848) ; mogiana Carrera (1955) ; nitida 

 Wiedemann (1830) [ = interlineata Walker (I860)]; 

 nodosipes Enderlein (1914); obscuripennls Enderlein 

 (1914); oculata Fabricius (1805) [ = agalla Walker 

 (1849), minuta Bellardi (1861)] ; pardalina Hermann 

 (1926) ; pectinata Carrera (1955) ; pennipes Hermann 

 (1926) ; peruviana Hermann (1926) ; rufithorax Wiede- 

 mann (1828) ; scopifer Schiner (1868) ; spinipes Her- 

 mann (1926) ; stylata Pritchard (1938) ; uruguayensis 

 Lynch Arribalzaga (1882). 



Ethiopian: Holcocephala lambertoni Bromley 

 (1942); semitestacea Loew (1863); tibialis Macquart 

 (1846) ; umbripennis Loew (1857). 



Oriental: Ilolcocepliala concolor Walker (1861); 

 dorsalis Walker (1856) ; hirsuta Wulp (1872) ; pandens 

 Walker (1860) ; prytanis Walker (1849). 



Subgenus Arthriticopus Enderlein 



Arthriticopus Enderlein, Wiener Ent. Zeitung, vol. 33, p. 101, 

 1014. Type of subgenus : Arthriticopus nodosipes Ender- 

 lein, 1014, by original designation. 



This fly does not differ from Holcocephala Jaennicke 

 in any respect except the exaggerated hind tibia and 

 basitarsus. It will be easily recognized by the abrupt, 

 distal swelling of this tibia and the equally swollen 

 first tarsal segment. Length 10 mm. 



Only two species fall in this subgenus. These are 

 Arthriticopus nodosipes from Colombia and Arthriti- 

 copus scopifer from Brazil. They may very well 

 prove to be the same species, as has been suggested by 

 Pritchard (1938). 



Genus Khipidocephala Hermann 



Fioubes 20, 37, 428, 843, 852 



Rhipidocephala Hermann, Verh. zool-bot. Ges. Wien, vols. 74-75, 

 p. 174, 1020. Type of genus: Discocephala analis Mae- 

 quart, 1840, by original designation. 



Quite small flies characterized by the high, dense, 

 long pilose mesonotum, the drooping abdomen, broad 

 wings and the reduced length of the third to seventh 

 tergites. The anal cell is widely open. These flies 

 are related to Ilolcocephala Jaennicke but are distin- 

 guished by the differently shaped antenna and long 

 pubescent or short plumose microsegment upon the 

 antenna, tho much narrower head, the long mesonotal 

 pile, and the open anal cell. The vertex is only slightly 

 or not at all divergent. Length 5 to 7 nun. 



Head, lateral aspect: The face is scarcely visible in 

 profile. The eyes are strongly convex anteriorly, gently 

 convex posteriorly, without ventral recession. The oc- 

 ciput is thick and well developed but obliterated at the 

 immediate vertex and also reduced near the bottom of 

 the eye. The pile of the occiput is composed of 1 or 2 

 rows of stiff hairs on the upper half and abundant, long, 

 fine, somewhat curled hair below; bristles absent. The 



