292 Professor E. B. Ponlton on Mimetic Forms of 



the Victoria Nyanza. It is unknown and probably 

 entirely wanting from the sub-species m^crope on the west 

 coast, but it may perhaps occur at the extreme eastern 

 development of the sub-species in Uganda. Its dis- 

 tribution is thus co-extensive with that of its Danaine 

 models the forms of Amauris echcria and cdbimacuktta. 



(a) Evidence of diaposcniatic mimicry hchveen the cenea $ /. 

 of P. dardanus and two species of the Danaine genus 

 Arnauris. 



It has been shown on p. 286 that the squarish shape of 

 the large pale patch on the hind-wing of the female forms 

 of dardanus is extremely ancestral, and the question arises 

 as to whether Amauris echcrict and albimacidata have not 

 mimicked and indeed exasfgerated this feature in the 

 Papilio which in other respects has mimicked them. There 

 are many reasons in favour of diaposematic relationship 

 between Danaine and Pa^nlio. The squarish patch in the 

 two species of Amauris, although far more marked than in 

 the cenea form, is in all probability a recent development. 

 It shows remarkable synaposematic sensitiveness, losing 

 much of its characteristic shai'pness and angularity in the 

 presence of other species of the same genus. This change 

 may be seen by a glance at Mr. S. A. Neave's Plate IX 

 in the present volume. Amauris albimacukUa ($ Fig. 2a, 

 $ Fig. o«) shows this change in the presence of Amauris 

 p)si/ttcdca, form damoclidcs, $ Fig, 2, ^ Fig. 3. Compare the 

 shape of the patch in the two sexes of alhimaculata, with 

 that of the same species from Natal far beyond the influence 

 oi damoclides, — $ Fig. 4, ^ Fig. 5. Amauris echeria is also 

 changed in the same direction by the presence of the 

 same model, as may be seen by comparing ,^ Fig. 2h and 

 $ Fig. 3& under the influence of damoclides ($ Fig. 2, 2 

 Fig. 3), with the same species from Natal — i^ Fig. 0, $ 

 Fig. 7. Amauris lohengida (Plate XXII, Fig. 1), closely 

 allied to A. echeria and probably ancestral to it, because 

 less peculiar in the genus, possesses a larger hind-wing 

 patch in which the square shape is not nearly so marked. 

 It is in fact almost precisely similar in shape to that of 

 the trimeni form shown on Plate XIX, Fig. 1, and the 

 hip)pocoon on Plate XVIII, Fig. 2. The exaggeration 

 of the feature in Amauris alhimaeulcda and echeria 

 is no reason against the hypothesis that it has been derived 

 by mimicry. In the great majority of the forms of Acrwa 



