THE BEMBA TRIBE OF NORTH-EASTERN RHODESIA    85
ciples of social grouping such as descent, age, sex differences, or local ties by which the tribe may be integrated and the incidence of authority determined; (d) the economic bases of the people's activities which affect their degree of dispersal, the form of leadership required, and the economic values associated with political prerogatives; (e) the type of foreign rule to which the tribe is subject and the European elements that are effecting its political development, i.e. variations in policy from the administrative system known as Indirect Rule in Tanganyika, Northern Rhodesia, Uganda, to the more direct government by the white man in South Africa or the attempts made to create new political institutions for Natives, such as the Bunga system of the Transkei.
All these factors will be found to account for differences in political organization among a number of the kindred peoples known as the Bantu, and I shall try to analyse the Bernba system along these lines.
/I. The Bemba Tribe
(a) Tribal Composition. The Bemba tribe at present inhabits the Tanganyika plateau of north-eastern Rhodesia, between the four great lakes—Tanganyika to the north-east, Nyassa to the east, and Mweru and Bangweolu to the north-west and west respectively. They number to-day about 140,000, very sparsely scattered over the country at a density of an average 3-75 per square mile.
The Bemba trace their origin to the area now known as the Belgian Congo and declare that they were originally an offshoot from the great Luba people which inhabits the Kasai district. The fact that the first ancestor of the Bemba is known as Citi Muluba ('Citi the Luban') substantiates this tradition, together with the cultural similarities still noted between the two peoples and the fact that Luban words, no longer understood by the Bemba commoner, are still used as part of the religious ritual at the paramount chief's court. The legends of immigration are numerous and circumstantial. The first arrivals apparently crossed the Lualaba River, which forms the western boundary of their present territory, about the middle of the eighteenth century, and travelled north and east until they established their first headquarters near Kasama, the present administrative centre of the Bemba country. From the sociological point of view, their history