some Bntish East African Butter Jlies. 517 



Is common on tlie 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 thoucrh 

 almost obsolete. It is very difficult to distinguish it from 

 Acr.va encedon on the wing, but it is I think both brighter 

 and lighter in colour. It is more active than most Aci^as, 

 but shares with these their remarkable resistance to 

 Potassium cyanide in the killing bottle.] 



[Mombasa, April 5, 1905. 



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

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

 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- 

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



4._ Papilionine Miviics. The mimetic females of the three 

 species of Pairilio 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 Painlio jaclcsoni (Fig. 2) and especially of P. 

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

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

 dardanus (mcrojye), probably sub-species tihuUus. 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 Pairilio mimics were taken at Nairobi on 

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

 though one species {P. jachsoni) was represented by the 

 male only which is not mimetic of Amauris. Another 

 point of interest is the local preponderance of Painlio 

 jaclcsoni where it is found. This preponderance at Kijabi 

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

 and suggests that the Pa'pilio may itself be distasteful to 

 certain enemies, but gains advantage in the adoption by 

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

 mimic, the Painlio 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 msect. 

 In nature the Painlio echerioides female is much nearer 



