Note 26 — Chapter V

Migratory birds have also been appealed to in another case where the resembling species are even further removed from one another than in the last case. Hypolimnas misippus is common and widely spread over Africa and Indo-Malaya, and the male (Pl. IV, fig. 8) bears a simple and conspicuous pattern—a large white spot bordered with purple on each of the very dark fore and hind wings. The same pattern occurs in the males of two other Nymphalines allied to H. misippus, viz. Athyma punctata and Limenitis albomaculata. The two species, however, have a distribution quite distinct from that of H. misippus, being found in China. It has nevertheless been suggested by Professor Poulton[26] that the case may yet be one of mimicry. According to his explanation, H. misippus is unpalatable, the well-known association of its female with Danais chrysippus being an instance of Müllerian mimicry. Migratory birds did the rest. Having had experience of H. misippus in the south, on their arrival in China they spared such specimens of Athyma punctata and Limenitis albomaculata as approached most nearly to H. misippus in pattern, and so brought about the resemblance. The explanation is ingenious, but a simpler view will probably commend itself to most. Other cases are known in which two butterflies bear a close resemblance in pattern and yet are widely separated geographically. Several species of the S. American Vanessid genus Adelpha are in colour scheme like the African Planema poggei which serves as a model for more than one species. The little S. American Phyciodes leucodesma would almost certainly be regarded either as a model for or a mimic of the African Neptis nemetes, did the two occur together. Nevertheless examples of close resemblance between butterflies which live in different parts of the world are relatively rare and serve to emphasise the fact that the great bulk of these resemblance cases are found associated in pairs or in little groups.