The surface of all this sub-region is described by Mr. A. R. Wallace as “generally open, covered with a vegetation of high grasses or thorny shrubs, with scattered trees and isolated patches of forest in favourable situations. The only parts where continuous forests occur are on the eastern and western slopes of the great Abyssinian plateau, and on the Mozambique coast from Zanzibar to Sofala. The whole of this great district has one general zoological character. Many species range from Senegal to Abyssinia; others from Abyssinia to the Zambesi; and a few, as _Mungos fasciatus_ and _Phacochærus æthiopicus_ (to which great numbers of species of insects may be added), range over the entire sub-region.” Various species of quadrupeds and birds are mentioned, which are found in Gambia, Abyssinia, and South-east Africa, but not in the West African sub-region; and yet Mr. Wallace adds, “Although this sub-region is so extensive and so generally uniform in physical features, it is by far the least peculiar part of Africa. It possesses, of course, all those wide-spread Ethiopian types which inhabit every part of the region; but it has hardly any special features of its own. The few genera which are peculiar to it have generally a limited range, and for the most part belong either to the isolated mountain-plateau of Abyssinia, which is almost as much Polar-Arctic as Ethiopian, or to the woody districts of Mozambique, where the fauna has more of a West or South African character.” Surely these circumstances, if correctly stated, together with the fact connected with the existence of the Great Sahara desert, extending many hundred miles wide across Africa, lead to the conclusion that the division of Africa south of the tropic of Cancer into three principal areas is unnatural, and that, with the exception of the necessary consequence of greater life-action within the tropics, there is so much uniformity in the animal productions of Africa as to render it (with our present knowledge at least) undesirable to cut up the continent into these sub-regions. Order LEPIDOPTERA. The Lepidopterous insects (butterflies and moths) especially attracted much of the attention of Mr. Oates; and of the day-flying species (Rhopalocera) he collected seventy-three different kinds, of which nineteen appear to be previously undescribed. As they form the most important part of his collection, I have given a complete catalogue of them in the following pages. These insects abound in certain districts, and in Mr. Trimen’s work on South African butterflies, as many as 226 different species are recorded.