Papilio dardanus (incropc) and Acriea johnstoni. 301 



part of the hind-wing and the apical part of the fore-wing 

 is marked by alternating dark and light stripes, — dark 

 veins, paler ground colour and again darker internervular 

 radii. This is certainly the conspicuous feature of the 

 insect during prolonged rest with closed wings hanging 

 downwards, and it is an appearance characteristic of 

 many Acnvina.'.* Hence in complete rest the prominent 

 characters are synaposematic with other Acrieinai ; during 

 fligbt and in brief rests with wings open the characters 

 are synaposematic with the genus Amauris. 



Oberthlir's form seuiialbesceois (1. c, Plate III, Fig. 29) 

 with white spots on the fore- wings and reddish-brown 

 hind-wings bearing a paler discal patch of the same colour, 

 may be looked upon as an exceptional variety of 'proteina. 

 It is of much interest as an example of the variational 

 material out of which natural selection has probably 

 produced such mimetic forms as fvlvcscens (Plate XXI 

 Fig. 4a), and toruna (Plate XXII, Fig. 3«.) 



(2) Acraia johnstoni, form Jlavescois, Oberthlir (1. c, PI. I, 

 f. 4). This form differs in the spots of the fore-wing being 

 buff instead of white. It is an obvious mimic of the buff- 

 spotted forms of Amauris cclicria. Every gradational 

 shade between pronounced buff and the pure white of 

 'proteina is to be found. A good intermediate example is 

 figured on Plate XXI, Fig. Ih, but the methods of photo- 

 graphy do not at present enable us to distinguish between 

 these pale tints. The remarks upon the under-side 

 colouring of proUina apply equally to fiavesccns. 



(3) Acrma johnstoni, form seinifuhescens, Oberthlir (I.e., 

 PI. II, f. 19). This is the form of the species described 

 by Godman from Kilimanjaro, and therefore from the 

 systematist's point of view the type of the species. From 

 every other point of view it is evidently highly specialized 

 — a comparatively modern offshoot from the ancestral 

 Amauris-mixnicWng forms ^jroi!cMi« or jlavescois. The 

 change has been brought about by selection in the direc- 

 tion of other models, Acrseiue in place of Danaine. There 

 are at least three different sub-forms included under semi- 



* It is also reproduced in tlie mimicry of Acrxinse,, e. g. in the 

 males of certain species of Pseudacrxa. In tlie magniticent W. 

 African Lyctenid, Epitola honorius, F., the portions of the under-side 

 exposed in prolonged rest are beautifully mimetic of this Acrseine 

 appearance, not only as regards tlie radiate markings Ijut also in the 

 characteristic group of black spots at the base of the hind-wing. 



