1915] on Mimicry and Butterflies a77 



butterflies, with an orange bar crossing the forewing and a white 

 bar the hind. In a forest in western Uganda, S. A. Neave found the 

 male of another species of Planema with both bars orange. In tlie 

 same forest the male Pseudacrsea had both bars orange, as had also 

 two other mimics, which at Entebbe resembled the male macarista — 

 viz. the female Acraea cdciope and the male Acraea althoffi. Two 

 examples of this last male were collected by S. A. Neave, and they 

 are unlike any form of the species that has been seen hitherto ; but 

 as regards the other two mimics similar forms are known to occur, 

 although in very small proportions, to the north-west of the Victoria 

 Nyanza. 



The geographical changes of the female Acrsea alciope in relation 

 to its models, may be considered in fuller detail. The female at 

 Entebbe with orange and white bars, is so unlike its non-mimetic 

 male that it was always regarded as a distinct species, until a few- 

 years ago the true relationship was made out by H. Eltringham. 

 On the west coast the female is less unlike its male, and has for long 

 been recognized as belonging to the same specie.s. The fine collec- 

 tions made by AY. A. Lamborn in the Lagos district shows that the 

 female alciope here mimics two or three species of Planema, but 

 especially the males of P. alcinoe. The orange bar of the forewing 

 is narrower and duskier in tint than in Eastern Uganda, while the 

 hind wing is also dusky orange, fringed with dark grey-brown, 

 almost black. There is considerable variation, as shoAvn by very 

 large nunibers of families bred by W. A. Lamborn. The non-mimetic 

 male, on the other hand, is very constant and almost precisely like 

 the equally constant male in Uganda. 



The great tropical forest of Africa stretches from the west coast 

 to the western borders of Uganda, and here, in the Semliki A^alley, a 

 small but intensely interesting collection was made by S. A. Xeave. 

 The western model of the female alciope continues right over the 

 whole area, but instead of being one of the commonest Planemas, it 

 becomes in LTganda relatively rare, and instead of having its 

 influence strengthened l)y the presence of other species with a similar 

 pattern, it is accompanied in Uganda by the far more abundant white- 

 barred P/rt;z^rr2^s, macarista m\K poggei. This change appears to begin 

 about at the Semliki Valley, and it is precisely here that many of the 

 females of alciop)e exhibit faint traces, especially upon the under 

 surface, of the white bar that becomes so conspicuous a feature in 

 eastern Uganda. Not a single specimen with a strongly marked 

 bar was collected by Neave in the Semliki Valley, and it is, there- 

 fore, impossible to regard these intermediate females as hybrids 

 between the western and the Entebbe forms of female. The transi- 

 tional geographical area where the white-barred Planemas begin to 

 appear yields the transitional females — the steps by which these 

 mimics transfer their allegiance from the males of the Planema alcinoe 

 type to that of the male P. macarista. 



