124 Mr. G. A. K. Marshall on Diaposematism, loith reference 



we should expect to find if the argument for reciprocal 

 influence were sound. 



It is by no means evident that this angular marking has 

 any real mimetic significance at all. In the more primitive 

 and non-mimetic $ $ of Pcq). merioncs and antinorii the 

 hind-wing is usually pale yellow, with three large, discon- 

 nected, submarginal black patches. The first step in the 

 mimetic approach towards the Danaines appears to have 

 consisted in the linking up of these patches to form the 

 continuous dark border so characteristic of the models. 

 An examination of the various forms of the $ dardanus 

 shows that the costal and median black patches usually 

 unite in a very characteristic manner, so as to give rise 

 to the angulation in question ; and we may reasonably 

 assume that a somewhat similar process took place in the 

 females. Now, it will be found that the development of 

 the angle is fairly constantly correlated with a com- 

 paratively narrow black border, and therefore it occurs 

 most frequently in the more primitive and less specialised 

 mimics, such as the forms trimeni and hippocoooioides, in 

 which the border is not broad. On the other hand, as the 

 inner edge of the border tends to approach the apex of 

 the discoidal cell, so does the angle become more or less 

 completely obliterated. In Amauris echeria and alhimacu- 

 lata the black border is very broad, and it will be found 

 that the specimens of P. dardanus f. cenea which present 

 the closest resemblance to them are those in which the 

 border is very broad and the angle consequently obliterated 

 (cf. Trans. Ent. Soc. 1906, PI. XVII, figs. 8-10, as against 

 fig, 11, which is a comparatively poor mimic). 



So far therefore from being able to accept the suggestion 

 that the angular marking has been produced in the 

 Amauris by the influence of the Papilio, it appears to 

 me that this merely transitional character in the Papilio 

 has had so little mimetic value that it is actually in 

 process of being eliminated by the influence of the 

 Amauris.* 



* It is interesting to note in this connection that neitlier Fajnlio 

 echerioides nor P. jacksoni has developed tliis angulation, although 

 they are excellent mimics of tlie same two species of Ainauris. 



