African Species of the Genus Acraea. 13 



A more interesting case is that of Acraea alcmpe, the male 

 of which varies but slightly throug-hout its range, whilst 

 the female, though still variable, appears in two pre- 

 dominant forms, the western form being dark brown and 

 mimetically associated with dominant western forms of 

 Planema, whilst the eastern or aurivillii form has an 

 orange band on the fore-wings and a white band on 

 the hind-wings, thus resembling the male of the dominant 

 eastern Planema. inncarista. 



A very remarkable case of sexual dimorphism is that 

 discovered by my friend Mr. S. A. Neave, who pointed out 

 that the transparent and almost immaculate A. eriistallina 

 is the fem.ale of A. chilo. A. honasia has two forms of 

 female, one of which is near the eynthius of Drury. Acraea, 

 penelcos has many female forms, one of which has just 

 been discovered in a long series of specimens bred by Mr. 

 W. A. Lamborn near Lagos, and two others are represented 

 by examples in the Hewitson collection, but appear never to 

 have been recognised or described. The first-named has 

 a lemon-yellow band across the hind-wings, in the second 

 the band is white and better developed, whilst the third 

 has the wings nearly black. It was the appearance of the 

 yellow-banded form which gave me the clue to the identity 

 of the white-banded examples, intermediates between this 

 and the black form leaving no doubt as to the identity of 

 the latter. Polymorphism of both sexes is of common 

 occurrence, and in some cases the forms are so extreme 

 that only by careful anatomical study can their true 

 relationship be established. Thus I have found that 

 Butler's A. astrigcra, a brilliant orange and red eastern 

 species, is specifically identical with the same author's 

 pseudolycia, the latter a black and white form of very 

 different appearance. Perhaps still more remarkable is 

 the discovery that Hewitson's little red, black and trans- 

 parent orestia is specifically identical with Miss Sharpe's 

 humilis, which in its extreme form is almost devoid of 

 colour, spots, or markings. 



One instance is known to me of polymorphism of both 

 sexes, accompanied by a geographically limited sexual 

 dimorphism. This complicated condition obtains in A. 

 lycoa. From its western limit to Mount Kilimandjaro it 

 presents a series of six different forms, in which however 

 the sexes are constantly different, the female having 

 the fore-wing spots white whilst those of the male are 



