to limitations of the Milllcrian Hypothesis of Mimicry. Ill 



III. Why do loth sexes of Archonias tereas miwAc only 

 the female o/Papilio zacynthus ? 



A second argument for Diaposematism has been based 

 on these same two species, considered from a somewhat 

 different standpoint. The case was stated as follows : 

 " So far as I am aware no explanation has yet been offered 

 of the fact that it is the females and not the males of 

 Papilio polymetus, P. zacynthus, etc., that are resembled by 

 Euterpe tei'eas and E. critias; Avhereas the males, which 

 display brighter colours, afford at least as good, if not 

 better, models for imitation, I would suggest that this 

 is really due to 'reciprocal mimicry.' The protection 

 gained by the resemblance between the Pierines and the 

 Papilios is not all on the side of the Pierines, but mutual ; 

 and the female Papilios have, as is usual, felt the need of 

 it more urgently than the males. For this reason the 

 female Papilios have been led to meet the Pierines by 

 discarding, or at any rate by not adopting, the bright 

 metallic-blues and greens that ornament the other sex," 

 (Trans. Ent. Soc. 1894, p. 298, note.) 



The colour of the $ P. zacynthus differs principally from 

 that of the $ in that the posterior two-thirds of the 

 fore-wing patch is covered with metallic-green or blue 

 scales, only the anterior portion being white ; whereas in 

 the ^ the whole patch is white. The contention for 

 reciprocal mimicry here centres entirely on the supposition 

 that it is difficult otherwise to explain why the Archonias 

 have not acquired the metallic patches of the male 

 Papilios, In considering this difficulty the first point 

 which suggests itself is to examine the occurrence of metallic 

 colours in other American Pierines. This inquiry reveals 

 the interesting fact that not a single one of these has 

 developed any metallic colours. The same limitation 

 holds good in Asia, as Wallace long ago pointed out, in 

 his classical paper on the Eastern Pierines : " The metallic 

 blue of Morp)ho and of the Lycsenidse, and the rich green 

 of various shades which occurs in most other groups of 

 butterflies are entirely absent " (Trans. Ent. Soc, 1867, p. 

 301). In fact, so far as I have been able to ascertain, it is 

 only in Africa that any Pierines have developed such 

 metallic scaling, and there it is confined to the males of 

 only two or three species of Teraeolus. But I cannot find 

 that any Pierine mimic has ever produced this type of 



