It has been attempted herein to indicate present and previous 

 nomenclatorial concepts of these species as clearly as possible, 

 especially for experimental workers and reviewers. Non_taxonomists, 

 who consider themselves "practical workers"', will imdoubtedly be 

 annoyed by the remainin[; confusion. The end is now in sight, and 

 within a very few years will undoubtedly be reached. A little 

 more patience will be rewarded by better understanding of what 

 has been an especially difficult conplex of variable species in 

 previously poorly explored parts of the v;orld. 



HYALavfl-IA DISTRIBUTION DI AFRICA 



Two species, H. trunc atun and H. rufipes , are common in drier 

 areas throughout the Ethiopian Faun"al Region (Figure l). Two 

 others, H. albiparmatum and H. impressun , are restricted to equa- 

 torial regions of Africa; these four species appear to have e_ 

 volved in Africa from Near Eastern stock. Only H. rufipes ex- 

 tends beyond the confines of the Ethiopian Region. Two other 

 species (H. detritum and H. marginatum ) range into North Africa 

 from the Near East and have tenuous, scattered footholds in the 

 transitional zones just south of the great deserts along the 

 northern periphery of the Ethiopian Region. Another Near Eastern 

 species, H. impeltatum , appears to be extending its range a little 

 more aggressively into East and West .Africa. The last species 

 known from continental Africa, H. turanicTim , has established it- 

 self in the South African Karroo after having been introduced on 

 sheep from the Near or Middle East. 



In East Africa, the arid lowlands along the Red Sea and the 

 Indian Ocean carry a number of Near Eastern and North African 

 species southwards into the Somalilands and parts of Kenya to- 

 wards and even slightly south of the equator. For instance, H. 

 dromedarii is known from the coastal lowlands of Kenya (Walker, 

 unpublished) and H. impeltatum occurs in scattered foci in 

 Kenya and Tanganyika. 



There is little question that other species do exist in nature 

 but their identity can be established only by breeding experiments. 

 The presence of a possibly undescribed species similar to H. drome- 



- 391 - 



