"B. atropos" is found in isolated populations of the mountainous regions of southern Africa. In South Africa, the species is known to occur in the Transvaal, along the Drakensberg escarpment of the eastern and northern Transvaal. Elsewhere in South Africa, it occurs in western Natal, Lesotho, and eastern Free State, and in the southern coastal mountains of western and eastern Cape Province. Spawls and Branch (1995) also mentioned, in Cape Province, its range extends into the Cape Peninsula. It also occurs in Swaziland, in higher altitudes of eastern Zimbabwe such as the Inyanga Highlands and Chimanimani Mountains, and in nearby Mozambique.