Though in the great majority of cases the imitator and the imitated occur in the same locality, this is not always so. The female of the Fritillary _Argynnis hyperbius_ (Pl. IV, fig. 3), for instance, is exceedingly difficult to distinguish from _Danais plexippus_ when flying, although when at rest the difference between the two is sufficiently obvious. Both insects are plentiful in Ceylon but inhabit different stations. The Danaid is a low-country insect, while the Fritillary is not found until several thousand feet up. The two species affect entirely different stations and hardly {53} come into contact with each other. Where one is plentiful the other is not found. It has been suggested that migratory birds may have come into play in such cases. The bird learns in the low country that _D. plexippus_ is unpleasant, and when it pays a visit to the hills it takes this experience with it and avoids those females of the Fritillary which recall the unpleasant Danaine. 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_ {54} _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.