92 R. W. CROSSKEY 



Subgenus FREEMANELLUM sgen. n. 



Type-species: Simulium berghei Fain, 1949. 



Diagnosis. 0*$ : Basal section of radius haired. Pleural membrane haired (apparently some- 

 times bare in $). Katepisternum haired. Fore tarsus slender, fore basitarsus 6-7 times as long 

 as its greatest breadth. $ : cibarium unarmed. Tarsal claws with large basal tooth. Scutum 

 rich reddish brown without pattern except for trace of three fine longitudinal lines. Abdomen 

 thinly covered with pale or coppery scales, not shining. Seventh sternite undeveloped. Gona- 

 pophyses slightly or distinctly produced tongue-like, tips rounded, directed rather downwards. 

 Paraprocts slightly, or large and very strongly, produced ventrally (Text-fig. 163). Sperma- 

 theca without or with weak traces of polygonal pattern, without internal hairs, o* : scutum as in 

 female. Genitalia with long slender curved styles as long as or longer than coxites, style with 

 one apical spinule ; coxite not produced beyond base of style but sometimes with inner spinous 

 process ; ventral plate of complex shape, not toothed, body of plate very strongly angled and 

 apex strongly haired, longer than wide, the basal arms parallel or slightly divergent ; plate with 

 a definite lobe developed between bases of basal arms ; median sclerite large, clove-shaped or 

 broadly dilated and slightly bifurcate apically ; parameres narrow elongate, parallel-sided or 

 contracting apically, with numerous subequal parameral hooks. Pupa : Gill much shorter than 

 pupal body, with four rather strong filaments arising near base, filaments sometimes swollen 

 basally or with minute pointed blackened tips. Abdominal onchotaxy normal, no super- 

 numerary hooks on segment 4 ventrally and terminal segments all without spine-combs dorsally. 

 Cocoon with well formed neck, often much produced anteroventrally. Larva : Head and 

 cephalic fans normal. Hypostomium with usual nine apical teeth but these extremely blunt and 

 sunken (Text-fig. 276) ; hypostomial setae 8-10 in each row, rows widely divergent posteriorly 

 from lateral margins of hypostomium, sides of hypostomium outside the setae very wide. Head- 

 spots positive, often merged into extensive dark pigmentation on cephalic apotome. Postgenal 

 cleft large, much longer than postgenal bridge, shape elongate-ovate in species known (Text-fig. 

 254). Mandible with very large primary brush extending well beyond apex (Text-fig. 295), 

 comb-teeth very large and longer than the rather reduced main apical tooth ; comb-teeth regul- 

 arly enlarging from first to third ; mandibular serrations normally two, inner margin of mandible 

 sometimes a little irregular. Antenna long and slender, pale, with four segments. Thoracic 

 cuticle bare. Abdominal shape normal, gradually expanding and widest at seventh or eighth 

 segment. Abdominal cuticle bare. Ventral papillae absent. Accessory sclerites absent. 

 Rectal scales apparently absent. Rectal gills with secondary lobules. Posterior circlet with 

 about 180-300 rows of 25-40 hooks. 



Bionomy. [Oviposition habit unknown.] Larval and pupal stages non-phoretic; 

 attached to rock surfaces and trailing rootlets in waterfalls or cascades, usually at 

 high altitude in hilly or mountainous areas. [Female biting preferences unknown, 

 probably ornithophilic] 



Distribution. An endemic Ethiopian subgenus known from eastern and southern 

 Africa with a distribution from north-eastern Congo and Uganda to the Cape (Map 

 8)*. One species recorded also from Guinea. Not known from Madagascar, where 

 the related subgenus Xenosimulium sgen. n. occurs. 



Discussion. The new subgenus Freemanellum is here proposed for a small group 

 of species that have hitherto been placed in the dentulosum-gvonp of Simulium by 

 Freeman & de Meillon (1953) or in the genus Anasolen (of which Simulium dentulosum 

 Roubaud is type-species) by Rubzov (1962) ; these species form a natural group of 

 orophilic cascade-inhabiting forms having several morphological characters and 



* Also in Nigeria and Liberia, see Appendix 



