66 R. W. CROSSKEY 



unrepresentative of the forms currently included in Eusimulium as a whole because 

 of the unique form of hypopygium, which is one of the most characteristic among all 

 Simuliidae : the coxites and styles and ventral plate (Text-figs. 102, 142) differ 

 strikingly from those of other species-groups of Eusimulium, and forms that are at 

 all similar for these structures occur elsewhere only in the Palaearctic subgenus 

 Wilhelmia. Despite this resemblance it is not likely that there is close phyletic 

 relationship between Eusimulium and Wilhelmia. 



The aureum-growp is an entirely Holarctic segregate, absent from the Ethiopian, 

 Malagasy, and Oriento-Australasian Regions ; in the New World distribution 

 extends southwards into Mexico and Guatemala, and the group therefore just 

 reaches into the northern fringe of the Neotropical Region. The Palaearctic 

 distribution includes Iceland, Canary Islands, North Africa and Middle East but 

 the group is apparently absent from Japan (no atireum-group species are recorded 

 from Japan by Ogata & Sasa, 1954 ; or by Rubzov, 1959-1964). On the African 

 continent the group occurs from Morocco to Tunisia. 



Rubzov (1959-1964 : 365-382) has treated the Palaearctic species of the group, 

 but has omitted the names of several supposed species of the group that have been 

 described from the Canary Islands (see below). S.(E.) aureum, with some supposed 

 synonyms, is the only species of the group in the Nearctic Region, but the name as 

 used in North American literature refers to an unrevised species complex (Stone, 

 1965 : 185). 



Included taxa. The included taxa for the African area are : — 

 Canary Islands : S.(E.) guimari Becker ; S.(E.) nigripes (Santos Abreu) ; 

 S.(E.) pseudolatipes (Santos Abreu) ; S.(E.) submorsitans Seguy ; S.(E.) velutinum 

 (Santos Abreu). [Note : Some or all of these names are almost certainly synonyms 

 of each other. Simuliidae of the Canary Islands need revision after collection of 

 the immature stages and study of associated adults.] 



North Africa : S.(E.) aureum Fries ; S.(E.) latinum (Rubzov). [Note : 

 Rivosecchi (1963 : 210) found only latinum represented in North African material 

 of the aureum-gvonp and records of aureum from the area may be due to mis- 

 identification.] 



Subgenus POMEROYELLUM Rubzov 



Pomeroyellum Rubzov, 1962 : 1492. Type-species : Simulium cervicornutum Pomeroy, 1920, by 

 original designation. 



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

 bare. Fore tarsus slender or at most very slightly dilated, fore basitarsus 5-7 times as long as 

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

 without conspicuous pattern. Abdomen usually bare and semi-shining on last few segments, 

 sometimes evenly covered with pale scales. Seventh sternite usually well developed. Gona- 

 pophyses simple bluntly rounded or truncate lobes. Paraprocts normal. Spermatheca without 

 definite surface pattern or internal hairs. <$ : scutum without bold pattern. Genitalia with 

 styles simple, tapering or bluntly truncate, shorter than or subequal in length to coxite ; style 

 with one apical spinule ; coxite not produced beyond base of style ; ventral plate not toothed, 



