SIMULIIDAE OF AFRICA 73 



instance, by Dalmat, 1955 ; Vargas & Diaz Najera, 1957). Some of the gill forms 

 in Hearlea tend to resemble those of S.(P.) cervicornutum, while others resemble 

 forms near S.(P.) unicornutum, but having regard to all the characters of Hearlea it 

 seems certain that the resemblances are due to convergence ; close phyletic affinity 

 between Hearlea and Pomeroyellum appears very unlikely. The gill in the cervi- 

 cornutum-gvonp species falls into two main types ; firstly, those like unicornutum in 

 which a thin-walled bladder-like gill is variously modified into barrel or sausage-like 

 (Text-figs. 190 & 192) form or takes on an almost amoeboid outline (Text-fig. 189), 

 and, secondly, the type of antler-like gill (Text-fig. 187) of cervicornutum that may be 

 a development from a gill with more stunted less definite branches (Text-fig. 188). 

 Until recently these two types of pupal gill in the cervicornntum-gvoup were rather 

 distinct, but the discovery of S.(P.) leberrci with its curious form of pupal gill (Text- 

 fig. 191, redrawn from Grenier, Germain & Mouchet, 19656) tends to bridge the gap 

 in form between the two types (although the nature of the leberrei gill is closer to the 

 unicornutum type than the cervicornutum type). 



There is a resemblance in the type of large inflated or irregularly branched gill in 

 some cervicornutum-group forms to the pupal gills of Simulium botulibranchium Lutz 

 from Brazil (figured by d'Andretta & d'Andretta, 1947) and of Paraustrosimulium 

 anthracinum (Bigot) from Tierra del Fuego (figured by Wygodzinsky & Coscaron, 

 1962), but such resemblance is clearly convergent. In the Oriento-Australasian 

 Regions there are no known forms with pupal gills like those of cervicornutum-gvonp. 



Included taxa. Simulium (Pomeroyellum) aureliani Fain ; S.(P.) blacklocki de 

 Meillon ; S.(P.) cervicornutum Pomeroy ; S.(P.) leberrei Grenier, Germain & 

 Mouchet ; S.(P.) palmeri Pomeroy ; S.(P.) pauliani Grenier & Doucet ; 5. (P.) 

 rotundum Gibbins ; S. (P.) unicornutum Pomeroy ; S.(P.) vangilsi Wanson. 



In addition the nomenclaturally unavailable form name bertrandi has been applied 

 by Luna de Carvalho (1962) to a taxon of this group. 



kenyae- group. £ hind basitarsus enormously enlarged, width about one-third of length ; 

 styles normal ; ventral plate with well developed shoulders and excavate sides, very deep in 

 profile (Text-fig. 122). Pupal gill with eight long filaments arising near base in regular pairs 

 (Text-fig. 184). Cocoon with neck. Larval abdomen posterodorsally with very small semi- 

 recumbent multifid setae (Text-fig. 223d) ) ; accessory sclerites absent. Larval postgenal cleft 

 very large, much longer than postgenal bridge, with flattened-cordate or transversely ovate 

 shape (Text-fig. 249) in which long axis is transverse. 



This group is proposed for the single species S.(P.) kenyae which certainly belongs 

 in the subgenus Pomeroyellum on its aggregate of characters, but which is so distinc- 

 tive in several features that it cannot satisfactorily be placed in any of the other 

 species-groups. The male differs from all other black-flies in the Ethiopian Region 

 by having the hind basitarsus very greatly dilated (figured by Freeman & de 

 Meillon, 1953 : 80), so that the length is only about three times the greatest breadth; 

 in other species where the male hind basitarsus is expanded the length is normally at 

 least four times as long as the width. The cocoon in kenyae has a well developed 

 neck, and thus differs from that of other species of Pomeroyellum, and the shape of 

 the larval postgenal cleft in which the width is greater than the length is very unusual. 



