34 



AFRICAN MIMETIC BUTTERFLIES 



Professor Poulton has suggested that the case is one of Miillerian rather than Batesian 

 mimicry.^ Unpalatabihty is essentially a relative rather than an absolute quality, and 

 it is easy to suppose that a species of slightly distasteful properties may strengthen its 

 position in the struggle for existence by resemblance to a still more distasteful kind. 



In Africa H. misippus is a very wary and active insect on the wing, especially when 

 alarmed. It would be of great interest to learn whether in America it has adopted the 

 habitually slow flight characteristic of very distasteful species. 



It occurs over practically the whole of the Ethiopian region, portions of South and 

 Southern North America, and the greater part of the Oriental region, extending to North- 

 West Australia and Queensland. 



PSEUDACRAEA POGGEI. 



Dewitz, Nov. Act. Nat. Cur. (41), ii, p. 197, pi. 2, f. 2 (1879). 

 Trimen, Proc. Zool. Soc, p. 79 (1891). 

 Butler, Trans. Ent. Soc, p. 202, pi. 10, ff. 2, 2a (1892). 

 Aurivillius (Synonymy), Rhop. Aeth., p. 175 (1898). 



Plate II, Fig. 11. 



As the name of this genus implies, many of its members bear a resemblance to the 

 Acraeinae. Indeed, the species of this genus may be said to exist for the most part by virtue 

 of their false colours, since with the exception of one or two forms they are all imitative 

 in both sexes of various protected species. To such a degree is this mimicry carried that 

 in many cases experienced collectors have been deceived, the models and their counterfeits 

 having been placed together in collections. P. poggei was described and figured by Dewitz 

 in 1879 as a species of Diadema [Hypolimnas) } Both sexes of the species are represented 

 in my own collection by examples from Johnstone Falls in North-East Rhodesia, and the 

 female is figured on Plate II. The male differs very little from the figure, though it is rather 

 smaller and its fore-wings are not so prolonged. Mr. Neave, who has had great experience 

 of collecting in Tropical Africa, considers this species to be by far the most perfect mimic 

 of D. chrysippus which has yet been discovered. He describes it as quite indistinguishable 

 from its model when on the wing, a fact which may account for the comparative rarity 

 of the species in collections since it is not really rare in the localities where it occurs. Until 

 comparatively recently not a single example of this butterfly existed in the National Collection. 

 Between October, 1898, and January, 1899, a collection of butterflies was made by native 

 collectors under the direction of Pere Guilleme at Kayambi in North-East Rhodesia on 

 the Chambezi River, and the specimens some seven years later were given to Mr. Byatt, 

 who presented them to the Hope Department at Oxford. The same collector communicated 

 a short paper on the subject to the Entomological Society in April, 1905. In it he describes 

 how, with a total of 367 typical chrysippus, there were found seventeen examples of Pseud- 

 acraea poggei, representing a proportion of mimic to model of only 4^ per cent., and even 

 this being a much larger proportion than was formerly supposed ; the author expressed 

 the opinion that the mimicry appeared to be Miillerian rather than Batesian. At the 

 February, 1908, meeting of the Entomological Society, Professor Poulton read a letter 

 from Mr. Neave, who was then collecting in the Congo Free State. The writer there says, 



^ Proc. Amer. Assoc. Ad. Sci., p. 242, 1897. The the genus Pseudacraea, instead of to Hypolimnas, in 



argument is further extended in the same author's which it had been included by Dewitz. The same 



essay, ' Thomas Henry Huxley and the Theory of author also pointed out the imitation of chrysippus 



Natural Selection, "Essayson Evolution.' Oxford, 1908. as being even more perfect than that of the female 



2 In the reference given above Trimen pointed misippus. The example then described was taken at 



out the true affinity of this butterfly, assigning it to Omrora, Ambuella Country, Angola. 



