MIMETIC ASSOCIATIONS 



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' Mimacraea marshalli, Trim., and Pseudacraea poggei were just beginning to reappear at 

 the end of October, and I have taken one of each. ... I still think P. poggei the best mimic 

 of Danaida {Limnas) chrysippus, even better than misippus — its flight is so extraordinarily 

 like that of its model. It is rather, I think, a significant fact that of all the Pseudacraeas 

 I have met with (5 spp.), poggci is by far the most abundant ; while it is bold and not 

 afraid to expose itself on the wing.' Mr. Neave has since told me that the species is by no 

 means rare where it occurs. On one occasion he noticed a specimen of chrysippus and one 

 of poggei behaving in a manner that suggested that one of the insects certainly mistook 

 the other for an individual of its own species. 



The example described by Butler came from Angola and is in the Tring museum. 

 Mr. Trimen informs me that there is a female in the collection of Mr. Hobley which was 

 taken in German East Africa. In order to be quite certain of the locality of the Tring 

 specimen I wrote to Dr. Jordan on the subject, and he very kindly replied that the locality 

 was quite correct, so that we evidently have a very wide range for this insect. 



ACRAEA ENCEDON. 



Linnaeus, Syst. Nat., ed. 10, p. 488 (1758). 

 Linnaeus [encedonia), Syst Nat. ed. 12, p. 762 

 (1767). 



Boisduval (sganzint), Voy. Deleg., ii, p. 590 

 (1847). 



Doubleday and Hewitson (fulva), Gen. D. Lep,, 



p. 140, pL 19, f. 2 (1848). 

 Wallengren [lycia), Rhop. Caff., p. 22 (1857). 

 Staudinger (ab. infuscata), Exot. Schmet., i, 



p. 83 (1885). 

 Aurivillius (ab. alcippina), Rhop. Aeth., p. iii 



(1898). 



Boisduval (ab. sganzint), Fauna. Madag., p. 34, 

 pi. 6, f. 6, 7 (1833) 



Fabricius (ab. lycia), Syst. Ent., p. 464 (1775). 

 Staudinger {braunei), Exot. Schmet., i, pi. 33 

 (1885). 



Hewitson (ab. necoda), Exot. Butt. Acraea, 



pi. 2, f. 9 (1861). 

 Godman and Salvin (ab. daira), Proc. Zool. 



Soc, p. 221, pi. 17, f. 3 (1884). 

 Trimen [encedon ab. ?), S. Af. Butt., i, p. 165 



(1887). 



Vuillot (usagarae). An. E. Fr., 60 Bull., p. 78 

 (1891). 



Butler {caecilia), Proc. Zool. Soc, p. 566 (1894). 

 Aurivillius (Synonymy), Rhop. Aeth., p. 110 

 (1898). 



Plate III, Figs, i, 2, 3. VIIL Fig, 16. 



The genus Acraea is one which provides models for many mimetic butterflies in the 

 African region, though in some cases the species are apparently drawn away into mimetic 

 association with other dominant forms. They fly slowly, without any regard for concealment, 

 and though gregarious in habit seem to be of quarrelsome disposition, and Mr. Trimen 

 describes how two females of Acraea horta, observed by Mrs. Barber, struggled for a long 

 time over the possession of a particular leaf of the food plant and ended by laying their 

 eggs on each other and flying away with them. They are for the most part of a very 

 conspicuous appearance, and the abundance of individuals, slow flight, and disregard 

 for concealment point strongly to the possession, by most species at least, of properties 

 which protect them from insectivorous enemies. They possess an offensive odour, which 

 appears to be caused by a yellow fluid which is exuded from the thorax when the insects 

 are handled. 



Acraea encedon is most remarkable in having developed three principal varieties which 

 correspond to varieties of D. chrysippus, in the same way as do the forms of H. misippus. 

 In the typical form, Plate III, Fig. i, the mimicry is that of the type form of D. chrysippus. 

 The specimen I have illustrated is of medium size, but many examples are much larger, 

 presenting a correspondingly closer resemblance to the model. The mimetic nature of the 

 pattern was first pointed out by Professor Poulton at a meeting of the British Association 



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