ENTOMOLOGY 861 
nus coniformis Ricardo, T. diversus Ricardo, 7. maculatissimus Macquart, 
7’. medionotatus Austen, T. nyasae Ricardo, T. obscuripes Ricardo, T. sharpet 
Austen, 7’. variabilis Loew, Haematopota brunnescens Ricardo, H. copemani 
Austen, H. hirsutitarsus Austen, H. insatiabilis Austen, H. masseyi Austen, 
AH. sanguinaria Austen, and H. stimulans Austen. In addition several species 
are known only from Upper Katanga, but most of these will probably be found 
in Rhodesia also: Hinea dubiosa Mich. Bequaert, Philoliche infusca (Austen), 
Dorcaloemus candidolimbatus Austen, Ommatiosteres bukamensis (J. Bequaert), 
Nuceria inornata (Austen), N. neavei (Austen), N. virgata (Austen), Chrysops 
neavet Austen, T'abanus brodeni J. Bequaert, 7’. gedoelsti Surcouf, 7’. lufirensis 
J. Bequaert, 7. muluba J. Bequaert, and Haematopota cruenta Austen. Very 
few tabanids are found in the higher mountains of the eastern Congo and only 
two of them appear to be typical of the montane region proper, v7z., T’abanus 
ruwenzorit Ricardo, of Ruwenzori, and Haematopota hirta Ricardo, of the 
Virunga volcanoes. 
The most interesting cases of distribution are those in which species that 
are common in the savannas of the East-and-South African Subregion are 
replaced in the rain forest of the West African Subregion by closely allied forms, 
so-called vicarious or substitute species. The following are a few examples 
of such pairs, the East African form preceding the West African in each case: 
Dasycompsa apiformis (Neave) and D. cincta Enderlein; Chrysops stigmati- 
calis Loew and C. distinctipennis Austen; Tabanus maculatissimus Macquart 
and 7’. trroratus Surcouf; Haematopota vittata Loew and H. ochracea (Bezzi). 
When the relationships between the species are better understood, many other 
cases of this kind will be discovered. It is obvious that the members of such 
pairs are genetically related, having been evolved either from each other or 
from some common ancestor. 
* Mesomyta fallax (Austen). * Chrysops brucet Austen. 
* Dasycompsa cincta Enderlein. i “ dimidiata van der Wulp. 
Hinea dubiosa Mich. Bequaert. * : distinctipennis Austen. 
* “ ~ rodhaini (J. Bequaert). * ‘«  funebris Austen. 
* Tabanocella innotata (Karsch). . griseicollis J. Bequaert. 
. perpulcra (Austen). ¥ te langi J. Bequaert. 
ee i stimulans (Austen). im es laniger Loew. 
si - umbraticola (Austen). i ed longicornis Macquart. 
* Thriambeutes austent (Hine). ix es neavet Austen. 
* re singularis Grinberg. Be - silacea Austen. 
* Subpangonia gravott Surcouf. i - stigmaticalis Loew. 
* Philoliche infusca (Austen). * Tabanus africanus G. R. Gray. 
= ~ oldii (Austen). ¥ e argenteus Surcouf. 
* Stenophara rodhaini (J. Bequaert). * a atrimanus Loew. 
Dorcaloemus auricomus Austen. - bestt Surcouf. 
* a candidolimbatus Austen. = “ biguttatus Wiedemann. 
* = compactus (Austen). * me : var. croceus Surcouf. 
* Ommatiosteres bukamensis (J. Bequaert). " m var. unimaculatus Mac- 
* Nuceria inornata (Austen). quart. 
* * — mayombensis J. Bequaert. ae billingtont Newstead. 
*  « —~ neavet (Austen). ’ is boueti Surcouf. 
- ‘“  schwetzi (Austen). ‘i iy brodeni J. Bequaert. 
* “ virgata (Austen). * brucei Ricardo. 
