528 Rev. K. St. Aubyn Rogers' Bionomic Notes on 



The relation of the eastern and western sub-species of 

 Fsevdacr/ea hoisduvali to their respective Acraiine models 

 is interesting and peculiar. There can be no doubt that 

 the eastern sub-species trimcnii with its conspicuous sub- 

 apical yellow-ochreous fore-wing bar, mimics Acrwa acara 

 (in which the apical portion of the fore-wing is warm red- 

 dish-ochre), and bears no very close resemblance to arcca or 

 to any of the other large red black-marked eastern Acrasas. 

 The western hoisduvali, on the other hand, is a much 

 closer mimic of Acnect cgina, the western representative of 

 arcca, than it is of zetcs, the representative of the eastern 

 model of trimcnii. This is all the more remarkable because 

 zetcs is replaced by acara in the Cameroons, as I was 

 astonished to find in the collection of the Brussels Museum. 



This mimetic relationship is unusual, and is all the 

 more remarkable because the eastern mimic is transitional 

 into the western, the eastern model into the western zetcs, 

 the western model into the eastern egina. It is probable 

 that this curious relationship is to be explained by the 

 fact that acara is, on the whole, predominant over arcca 

 in the range of trimcnii, and cgina (the W. representative 

 of arcca) predominant over zctes (the W. representative of 

 acara) in the range of hoisduvali. (Compare Mr. Roland 

 Trimen's account on pp. 552-554.*) 



A very interesting detail in the mimetic resemblance 

 of the Pscudacrma is to be seen in the palpi, which are 

 orange like those of Acrma acara, A. arcca, A. ancmosa, 

 and A. natalica. A parallel case is to be found in the 

 3fcthona-Thyridia-cenived combination of tropical South 

 America, in which the yellow or orange-clubbed antennae 

 of the models are mimicked by Danainm (Ituna), Picrina^ 

 {Dismorphia) and Castniid moths. In both cases the 

 small size of the mimetic feature is probably compensated 

 by its prominence. E. B. P. 



c. Comhination of small fulvous and hlaeJc Aeneas from 

 Wcithaga. 



This group consists entirely of species of the genus 



* Just as Mr. Trimeu finds obvious links with the western boisd'x,- 

 vali in the pattern of certain eastern individuals, and especially 

 one of the Kabai specimens here referred to, so also a clear transition 

 towards the eastern trhnenii may be seen in Angolan specimens in 

 which a trace of the ochreous sub-apical fore-wing bar is present. 

 It is however probable that acara and not zetes is the Angolan form. 



