38 PKOCEE DINGS OF THE 



males. Thus the mimetic female forms of PapiJlo dardanus bear 

 in this respect the same relation to their Danaine models that 

 they bear to their own male, and the female of the non-mimetic 

 ancestor F. meriones in Madagascar is also far less eulegnic than 

 its male. Th« dyslegnia has preceded the mimicrv. If the 

 brighter colours of male butterflies have been developed by sexual 

 selection — and the fact that male brilliaacy is due to interference 

 colours as well as pigments strongly supports the Darwinian 

 interpretation — it is also highly probable that their more eulegnic 

 patterns have arisen in the same way. 



When the sexes of a mimic are alike the male pattern as well 

 as the female tends to be dyslegnic. This is commonly true in 

 both sexes of the mimetic swallowtails of the section Cosmodesmus, 

 as it is of the mimetic females of Papilio. An excellent example 

 has already been described in the fore wing of Ildiconius nanna 

 with both sexes alike (p. 34). 



In order to test the prevalence of dyslegnia in mimicking 

 butterflies, 1 examined a considerable series selected many years 

 ago as illustrations, and without any thought of this characteristic. 

 Everywhere in the series the mimics were dyslegnic as compared 

 with the models *. They included Nymphalines of various genera 

 and Papilios of various species mimicking Danaines, Nymphalines 

 mimicking Acrseines, and Acrtea natalica mimicking A. anemosa. 

 The principle was commonly manifested by the Papilionine 

 mimics of the PharmacopluKjxis Papilios of which a long illustra- 

 tive Series has been arranged in the Hope Department. One of 

 the most striking examples is provided by the strongly dyslegnic 

 patterns of all the forms of Elifmnias, mimicking Dauaine and 

 Pierine models in the East and Acreeine in Africa. 



Having thus examined a number of well-known examples I 

 thought it would be interesting to apply the test to newer 

 instances only recently worked out in detail. Accordingly the 

 attempt has been made to set forth in tabular form (Appendix, 

 p. 51) the condition of Ihe pattern edges in a series of similar 

 patterns belonging to the two sections of the Ueliconince referred 

 to on p. 35. The series itself is fully described and illustrated in 

 Dr. Eltringham's memoirt on the JUdiconime now in the press 

 and to appear shortly in the Transactions of the Entomological 

 (Society for the present year. Dr. Eltringham has kindly read 

 the tabular statement and confirms the descriptions. Mr. W. J. 

 Ivaye, with a wide experience of the relative abundance of the 



* The only exception that- I encoiintererl -was tlie alcgiiic transition from 

 orange-brown to black in tlie fore wing ut iJanaida chrysijipus. In tiiis bulter- 

 lly and its miinic, the female Hypvliiiinas riiis'rppus, this transition appears to 

 be real, being brought about by a gradual darkening in the colour of the 

 pigment in the scales as the black area is apjiroached — not by the "stippling " 

 of the usual dyslegnic margiia. In other respects the j^attern of D. chn/srppus 

 is eulegnic (see ]). 42). It is interesting to note that this alegnic transition 

 from orange- brown to black is associated w'ith extraordinary variabih'ty in the 

 relative areas of the fore wing occupied by these two shades. 



t Sec ISoLet p. 34. 



