94 R- W. CROSSKEY 



At the present time little material is available of Freemanellum species and only 

 berghei Fain and debegene de Meillon are so far known in the larval stage (the fore- 

 going diagnosis may therefore need modification when more material and all stages 

 of all species are known). The larvae of both berghei and debegene have a rather 

 exceptional mandible : the primary brush is extraordinarily produced apically and 

 very conspicuous beyond the end of the mandibular body, as shown for berghei in 

 Text-fig. 295 ; the brush in debegene is also produced but appears to be strongly 

 curved round in a similar way to that of S. (Xenosimulium) imerinae (Text-fig. 296) ; 

 in both species the comb-teeth are excessively large and the main apical teeth reduced 

 so that they are no larger than the comb-teeth (Text-fig. 301). These larval mandi- 

 bular characters help in distinguishing the larvae of Freemanellum from those of 

 Anasolen and Metomphalus, with which they sometimes occur in cascading streams. 



The distribution of subgenus Freemanellum is disjunct on present evidence, there 

 being a main centre of distribution along the south-eastern side of the African 

 continent (Map 8) and an isolate in the extreme west of West Africa. The West 

 African locality is based upon a single pupa, apparently of S.(F.) debegene de Meillon 

 (specimen in BMNH : examined), recorded by Garms & Post (1967) from Guinea. 

 It is unlikely that such an extreme break in distribution really exists, and species of 

 the subgenus are here presumed to occur in intermediate areas although they have 

 not yet been discovered there*. 



Included taxa. Simulium (Freemanellum) berghei Fain ; S.(F.) debegene de 

 Meillon ; S.(F.) empopomae de Meillon ; S.(F.) hessei Gibbins ; S.(F.) hirsutilateris 

 de Meillon. 



Subgenus WILHELMIA Enderlein 



Wilhelmia Enderlein, 1921 : 199. Type-species : Atractocera lineata Meigen, 1804, by original 

 designation. 



Diagnosis. 5*$ : Basal section of radius haired. Pleural membrane haired. Katepisternum 

 bare. Fore tarsus slender, fore basitarsus six or seven times as long as its greatest breadth. 

 Hind basitarsus 1 -15-1 -25 times as long as remainder of hind tarsus (cf. Metomphalus). $ : cib- 

 arium unarmed. Tarsal claws very enlarged (about two-thirds as long as third fore tarsal seg- 

 ment and longer than width of this segment), without basal tooth. Scutum greyish with three 

 fine longitudinal dark lines meeting posteriorly to form lyre-shaped mark (Text-fig. 72). Abdo- 

 men uniformly silvery-scaled. Seventh sternite undeveloped. Gonapophyses forming slender 

 curled acuminate processes. Paraprocts normal. Spermatheca without internal hairs. <J : 

 scutum greyish black to velvety black with or without a pair of large silvery grey triangular areas 

 anterolaterally. Genitalia with very small styles and enlarged coxites, style usually folded 

 down against body of coxite, with one apical spinule ; coxite at least slightly produced beyond 

 base of style ; ventral plate subtriangular in form with elongate basal arms which are usually 

 widely divergent, body of plate not toothed ; median sclerite toothed, usually bifurcate or 

 clubbed apically, sometimes rounded ; parameres long and slender, parameral hooks numerous. 

 Pupa : Gill formed of enlarged thin-walled unornamented tubular basal arms, oriented dorso- 

 ventrally, between which arise medially several (usually 6) tubular filaments directed forwards 

 (Text-fig. 207) ; medial series of branches sometimes short and stout. Abdominal segments 6-9 

 dorsally without spine-combs. Cocoon with well formed neck, shoe-shaped. Larva : Head and 



* See Appendix 



