The Bionomics of SoiifJi African Insects. 469 



sub-apical wliite bar present in the female of typical 

 doubled cci/i. The presence of the male indicates, however, 

 that the female flies with the other members of this 

 cJ/ri/sipjyits-like group, of which it forms an imperfect and 

 outlying constituent. The male of soma, also docs not 

 resemble cho'i/sippifs, w\\\\o the female is an even more 

 imperfect Mlillerian mimic than the female of douUcdciyi. 

 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. 

 cncedony 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 Ama.uris, 

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

 whicli surrounds L. chrysippus, recalls a principle already 

 Avell known and probably correctly understood in the case 

 of Batesian mimicry. When an abundant well-protected 

 Acrxa thus approximates to two very different J)anaine 

 patterns it is obvious that we are not necessarily driven to 

 a Batesian interpretation of the forms of the female Fapilio 

 cenca, which approximate to the appearance of Amauris 

 echeria as well as to the two other Danaine types alluded 

 to above. The enemies of clurysippus 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 tlie likeness to two or three models is 

 even more obvious. 



