Notes on some British East African Butter flies. 557 



within the range of this Danaine's predominance or 

 prevalence. 



Everywhere exceptionally productive in differing forms 

 and intermediate variations, the % P. dardanus is surpass- 

 ingly protean, as the smaller-sized sub-species loolytrophus, 

 in its modifications in the elevated interior of British East 

 Africa, especially on the Kikuyu and other " Escarpments " 

 immediately north and south of the equator. There, as 

 Prof. Poulton has ably demonstrated,* it is possible to 

 trace, with the aid of the many still existing gradations, the 

 highly probable derivation of the more prominent mimetic 

 forms from the primitive trimcni-ioxm. which is compara- 

 tively so little divergent from the male coloration and 

 pattern. The transitional series from trinuni, — through 

 (1) liipiwcoon and the partly fulvous-coloured linking 

 variations between trimeni and tropJionius ; (2) those be- 

 tween hip2)ocoon and troplwnius ; and (3) those between 

 trophonius and doripp)oides — well exemplified by the 

 wholly fulvous-marked trophonius described by Prof. Poul- 

 ton (I.e., p. 290) ; — constitutes a most striking and convinc- 

 ing illustration of the action of natural selection in the 

 evolution of multiform mimetic adaptation within the 

 limits of one sex only of a single species. 



* Trans. Ent. Soc. Lond., 1906, pp. 283-298. 



Explanation of Plates XXVI-XXIX. 



[See Explanation facing the Plate-^. 



