R. simus senegalensis ; the last two forms have limited extensions 

 into East Africa. West African forest species, in the Sudan known 

 only from montane forests and lower streambanks of the Imatong and 

 nearby mountain masses of the east bank of Equatoria Province, are 

 H. par mat a , R. bequaerti , and R. kochi . The Imatong Area also 

 harbors several specialized Ea"st African forms not found elsewhere 

 in the Sudan. 



The occurrence of popvdations of any of the first five species 

 listed above outside of the Raga_Loka Area (Figure 328) is excepL. 

 tional. 



„ It should be noted that the term West African, as here vised 

 zoogeographically, applies to elements originating in the first 

 six of the Faunal Districts listed in Figure 1. Several species 

 logically considered as West African from a generalized point of 

 view and in common name terminology are not considered West Afri- 

 can in the more strictly defined zoogeographical sense of the 

 terra. For instance, H. impressum , although confined to West 

 Africa in the generalized geographical sense, is a savannah spe- 

 cies of the East African (zoogeographical) Subregion. H. houyi 

 appears to be common in the savannahs of both Subregionsj aJU 

 though it is difficult to determine in which Subregion it shoiild 

 be considered typical the evidence strongly suggests East Africa. 



M. reidi sp. nov. is tentatively incliided here as a species 

 of the West African Subregion since it has been found in only a 

 restricted sector of the Raga_Loka Area (Figure 328) . Fiirther 

 investigation may modify this concept but it is unlikely that a 

 large amount of data will ever be amassed on this curious spe- 

 cies. The iinique biological characteristics and distributional 

 picture of the two species in this genus, combined with their 

 localization in remote areas, confuse an interpretation of their 

 pattern of distribution. 



East African Components 



Species limited mostly to the area politically considered 

 as East Africa are of considerable value as zoogeographical 

 indicators for the present st\ady. The fact that several of these 

 species, stich as Amblyonma gemma and Rhipicephalus pulchellus , 

 are not known to reach the Sudan, is of additional interest. 



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