SIMULIIDAE OF AFRICA 61 



Included taxa. The group includes the following forms from the Regions 

 indicated : 



Palaearctic Region : all taxa assigned to the latipes-gvoup in Rubzov (1959- 

 1964), one of which occurs in North Africa : S.(E.) costatum Friederichs. 



Nearctic Region : S.(E.) aestivum Davies, Peterson & Wood ; S.(E.) bicorne 

 Dorogostajskij, Rubzov & Vlasenko [also in Palaearctic Region] ; S.(E.) croxtoni 

 Nicholson & Mickel ; S.(E.) gouldingi Stone ; S.(E.) impar Davies, Peterson & 

 Wood ; S.(E.) latipes (Meigen) [also in Palaearctic Region] ; S.(E.) pugetense 

 (Dyar & Shannon) ; S.(E.) quebecense Twinn ; S.(E.) wyomingense Stone & De 

 Foliart. 



Oriental Region : S.(E.) tjibodense Edwards ; S.(E.) tosariense Edwards. 



ru/icorne-group ( = angustitarse-group). Postnotum bare. Styles simple and bluntly 

 truncate (Text-figs. 143 & 144) ; ventral plate large and broad, with haired median keel, basal 

 arms directed forwards ; parameres narrow and elongate (Text-fig. 88), each bearing one long 

 strong parameral hook (occasionally a minute supernumerary hook or spine near base of main 

 hook) ; median sclerite elongate and rod-like or slightly clubbed, not noticeably bifurcate (ex- 

 cept in loveridgei) . Pupal gill with 4 or 6 filaments ; when 4 filaments present these sometimes 

 arising from paired or single large trunk (Text-fig. 180), or one or two of them reduced thumb- 

 like (Text-fig. 179), very rarely one lost completely so that gill may have only 3 filaments in 

 some specimens. Cocoon simple or with subtriangular median projection (usually not long horn- 

 like as in some latipes-gvoup forms). Larval antenna without secondary annulations, larval 

 mandible without supernumerary mandibular serrations. Larval postgenal cleft much shorter 

 than postgenal bridge, small rounded or subquadrate, forming a minute notch in posteroventral 

 margin of head or absent altogether (Text-figs. 242-244). 



This group was termed the ruficorne-gvoup by Freeman & de Meillon (1953) for the 

 Ethiopian fauna and the angustitarse-gvoup by Rubzov (1959-1964) and Davies 

 (1966) for the Palaearctic fauna, both names applying to the same species-group 

 concept. The name ruficorne-gvoup is here preferred as this has prior usage, and 

 S.(E.) ruficorne Macquart, 1838 itself occurs in both the Palaearctic and Ethiopian 

 Regions and has the widest distribution of any included species. 



The group appears not to be represented in North America, but has a wide distri- 

 bution throughout the Old World that includes Europe, North Africa and Canary 

 Islands, Middle East and southern Arabia, Central Asia, the Oriental Region, 

 Australia, New Guinea and New Caledonia, and the whole of the Ethiopian and 

 Malagasy Regions. It is undoubtedly closely related to the latipes-gvoup, from which 

 the immature stages on a group basis cannot be satisfactorily delimited, but differs 

 by the distinctive male ventral plate in which there is a characteristic haired median 

 keel (in the latipes-group the large broad plate has a haired down-bent lip but no 

 definite median keel) ; the male hypopygium also differs by having long slender 

 subparallel-sided parameres, differently-shaped styles (styles of latipes-gvoup 

 described above), and by the median sclerite not having a deep apical cleft. S.(E.) 

 loveridgei from St. Helena Island, which certainly belongs in the ruficorne-gvoup, is 

 an exception for the last character as it has a Y-shaped median sclerite (Crosskey, 

 1965a), although the prongs of the Y are shorter and less widely splayed than those 

 of latipes-gvoup species. The ruficorne-gvoup is distinguished from the loutetense- 



