Papilio danlanns {mcropc) and Aerica johnstoni. 299 



B. Mimetic forms of Acrxa johnstoni, Godman. 



Introductory. — In the following section the attempt will 

 be jnade to show that the whole series of diverse forms 

 which have given to this species its long synonymic list 

 has arisen through the development of mimetic likeness to 

 several distinct models, both Danaino and Acrseine. The 

 form-names suggested by Oberthlir * have been followed 

 throughout, Acriea tortina, Grose-Smith, being regarded 

 as a form of semifuhescens, Oberth. In a later part of the 

 section facts will be brought forward which appear to 

 prove that this protean butterfly is not only conspecific 

 with fallax, Rogenh. (= hilimandjara, Oberth.), as 

 Aurivillius suggests, but also with Godart's species, lycoa. 



I owe the opportunity of writing this part of the present 

 memoir to my kind friend, the Rev. K. St. Aubyn Rogers, 

 M.A., of Wadham College, Oxford, who has presented to 

 the University Collection the deeply interesting series of 

 models and mimics represented on Plate XX. The 

 whole of the butterflies there represented together with 

 other examples of the same mimetic forms were captured 

 on the slopes of Kilimanjaro in 1905. In addition to this 

 extensive material Mr. St. Aubyn Rogers has presented 

 many examples of A. johnstoni from Taita and Taveta in 

 British East Africa, including the fine and remarkable 

 variety from the last-named locality, represented on Plate 

 XXII, Fig. 2a. The series of models and mimics would 

 however have lacked completeness if other kind friends 

 had not also afforded valuable help : — Mr. Guy A. K. 

 Marshall sending me an extreme south-eastern form 

 (Plate XXII, Figs, la, 1&), with its model (Fig. 1); and 

 Mr. C. A. Wiggins the extreme western mimetic form 

 (Plate XXII, Fig. 3a) with the model (Fig. 3) from the 

 same district. 



The mimetic resemblance of the commonest forms of 

 A. johnstoni {iirotcina and Jlavesccns) to Danaine butterflies 

 of the genus Amauris was suggested by the present writer 

 in 1897.t Although greatly impressed by the likeness of 

 Acrseine to Danaine, I was then quite unaware of the 

 existence of this wonderful range of forms and of the 



* Etudes d'Entomnlogie : Dix-septieme Livr. : Avril 1893. 



■j" " Theories of Mimicry, as illustrated by African Butterflies," 

 read before Section D of the British Association at Toronto, Aug. 20, 

 1897. Abstract in Report of the Toronto Meeting, pp. 688-691. 



TRANS. ENT. SOC. LOND. 1906. — PART II. (SEPT.) 20 



