some British East African Butter files. 517 



is common on the Taita hills : the other form \_fulvescens'\ 

 I thought to be a different species until I perceived that 

 the white spots on the fore-wing were traceable though 

 almost obsolete. It is very difficult to distinguish it from 

 Acnea cncedon on the wing, but it is I think both brighter 

 and lighter in colour. It is more active than most Acraeas, 

 but shares with these their remarkable resistance to 

 Potassium cyanide in the killing bottle.] 



[Mombasa, April 5, 1905. 



A. johnstoni I have only found on the hills at 3000 ft, 

 upwards. I did not get it at Taveta, or indeed A. alhimacu- 

 lata, which also seems a hill insect.] 



[It will be seen by reference to the table on p. 515 that 

 soon after the above letter was written, forms of A. john- 

 stoni were taken at Taveta. E. B. P.] 



4, Papilionine Mimics. The mimetic females of the three 

 species of Papilio are well shown, two-thirds of the natural 

 size, on Plate XXVIII, together with their non-mimetic 

 males and chief Danaine model. It is seen that the 

 females of Fapilio jacksoni (Fig. 2) and especially of P. 

 echerioidcs (Fig. 4) are more perfect mimics of the Amau- 

 ris (Fig. 1) than the cenea female form (Fig. 6) of P. 

 darclanus (mcrope), probably sub-species tihvllus. The 

 latter happens to be a very imperfect specimen of a variety 

 tending towards the hippocoon female form and rather a 

 poor mimic. The series of specimens represented in 

 Plate XXIV of this year's Transactions (1907) shows that 

 the mimicry of the cenca form is usually better than in the 

 example here figured, I have already alluded to the fact 

 that all three Pajnlio mimics were taken at Nairobi on 

 the same day (see Figs. 3, 5, 6 and 7 on Plate XXVIII), 

 though one species (P. jacksoni) was represented by the 

 male only which is not mimetic of Amauris. Another 

 point of interest is the local preponderance of Pctpilio 

 Jacksoni where it is found. This preponderance at Kijabi 

 is, I think, fairly represented by the series obtained there, 

 and suggests that the Papilio may itself be distasteful to 

 certain enemies, but gains advantage in the adoption by 

 its female of a well-known Uanaine pattern. Although a 

 mimic, the Papilio may in its own habitat far outnumber 

 the model, which however has a much greater range and 

 is of course as a whole an infinitely more abundant insect. 



In nature the Papilio echerioiclcs female is much nearer 



