The Bionomicfi of Sov,fh Africnn Insect.'^. 469 



sub-apical white bar present in the female of typical 

 donhlcdayi. The presence of the male indicates, however, 

 that the female flies with the other members of this 

 (•liriisippus-\\ke group, of which it forms an imperfect and 

 outlying constituent. The male of scrcna also does not 

 resemble chrysvpims, while the female is an even more 

 imperfect Mlillerian mimic than the female of douhledayi. 

 Nevertheless such cases are of the highest interest, inas- 

 much as they enable us to understand how mimicry arose 

 in species which now exhibit a startling likeness. A. 

 encedon, one of the most perfect Mlillerian mimics of 

 chrysippus, presents an equally close approximation in 

 male and female. 



The fact that the female of P. esehria should present 

 two well-marked varieties, one of which falls into a black- 

 and-white group convergent round the species Amauris, 

 while the other, the type-form, enters the combination 

 which surrounds Z. chrysvpims, recalls a principle already 

 well known and probably correctly understood in the case 

 of Batesian mimicry. When an abundant well-protected 

 Acrxa thus approximates to two very different Danaine 

 patterns it is obvious that we are not necessarily driven to 

 a Batesian interpretation of the forms of the female Papilio 

 cenca, which approximate to the appearance of Amauris 

 echcria as well as to the two other Danaine types alluded 

 to above. The enemies of chrysippus and the species of 

 Amauris are certainly not precisely the same, and it may 

 well be an advantage to a Mlillerian mimic to secure that 

 increased protection from insect-eating enemies which is 

 conferred by belonging to two or more groups. 



Furthermore, the Planema has come to resemble the 

 Danaine and not the Danaines the Planema, and this 

 probably indicates that the Danaine is on the whole the 

 less attacked and the better known. It is probably of 

 advantage to the whole group that the Danaine which set 

 the pattern should still be the dominant member of the 

 assemblage of which it is the centre. This dominance is 

 favoured by the individuals of an abundant species joining 

 two or more groups instead of throwing the whole of their 

 number into a single one. In the case of Batesian mimicry, 

 where the mimics are comparatively palatable and would 

 be freely eaten if recognized, the advantage of this di- or 

 trimorphism and the likeness to two or three models is 

 even more obvious. 



