SIMULIIDAE OF AFRICA n 



to Grenierella in South America, but again convergence seems likely, and balance of 

 evidence points to an African origin for the Malagasy fauna. 



The most striking feature of the rich Simuliid fauna of the Ethiopian Region is its 

 endemicity : apart from ruficorne mentioned above, which occurs also in the 

 Palaearctic and Malagasy Regions, and with the possible exception of backleyi which 

 has been identified from Madagascar, there are no Ethiopian species that occur 

 outside the region, and almost all the subgeneric taxa are endemic (though often 

 with apparently related or parallel segregates in other regions). As with all other 

 regions except the Oriental Region (from which the Prosimuliini are absent on 

 present evidence) the fauna is an admixture of relatively primitive Prosimuliine 

 forms and of supposedly more advanced Simuliine forms, but in the Ethiopian Region 

 the Prosimuliine fauna is very impoverished and in number of species accounts for 

 only about 8% of the fauna (much less than in the Holarctic Regions, and less than 

 in South America — where, assuming that Gigantodax is included, about 14% of 

 species-composition of the fauna is Prosimuliine) : the overwhelming majority of 

 Ethiopian forms, as elsewhere in the world tropics, belong to Simuliutn s.l. 



The Prosimuliine forms in the Ethiopian Region (in the present work all placed in 

 the genus Prosimidium s.l. but in the past assigned to Cnephia) appear to be relict 

 remnants of a Prosimulium-\\ke fauna that was once widespread throughout Africa, 

 or such is the impression given by the few and widely scattered loci from which these 

 few presumed primitive forms are yet known. The morphological characters of 

 Prosimulium in the southern tip of the Ethiopian Region are slightly more 

 ' advanced ' than those of Prosimulium in Palaearctic Africa (in the sense that 

 spiniform costal macrotrichia are developed and the fork of Rs obliterated) but 

 geographically intermediate forms (known from Uganda and Rhodesia) are also 

 morphologically intermediate, and there is no real faunal break between Palaearctic 

 and Ethiopian Prosimidium ; there is no evidence to suggest that Ethiopian 

 Prosimuliine forms had a southern route of entry into Africa. 



Throughout most of the Ethiopian Region the only genus present in the black-fly 

 fauna is Simidium in the wide sense, and over 90% of Ethiopian species belong in 

 the genus. In the present re-classification ten subgenera are recognized in the 

 Ethiopian Simidium fauna, of which eight are endemic and confined to the region 

 (Pomeroyellum, Meilloniellum, Lewisellum sgen. n., Phoretomyia sgen. n., Anasolen, 

 Freemanellum sgen. n., Metomphalus and Edwardsellum), of which one occurs in the 

 Holarctic Regions as well as the Ethiopian (Byssodon), and of which one is cosmo- 

 politan or almost so (Eusimulium) . It is of interest to note that the number of 

 subgenera in the Ethiopian Region here accepted as valid (10) conforms closely to 

 the numbers in the Nearctic and Palaearctic Simulium fauna : Stone (1965), for 

 the smaller fauna of North America, accepts nine subgenera, and Rubzov (1959- 

 1964) — though ranking them as full genera — recognizes eleven genus-group segre- 

 gates in Simidium sensu lato in the Palaearctic Region : thus there is close taxon- 

 omic balance in the categories which it is considered desirable to recognize as named 

 segregates of Simidium s.l. between the present reclassification for the Ethiopian 

 Region and the classifications already existing for the Holarctic area. The Simulium 



