820 Explanation of Plates. 



Fig. 16. Acrseajohnstoni, form jyrofeina, $, from the same locality 

 as 1 and la. Cajitured by Mr. Marshall, October 11, 

 1905. The female exhibits a patch even larger than that 

 of the male, and of a shape which approximates more 

 closely to the model shown in Fig. 1. 



2. Planema poggei, Dew., ^ , from Buddii, between Entebbe 



and the mouth of the Kagerii Kiver, west shore of Lake 

 Victoria Nyanza ; collected December 3, 1902 — March 1, 

 1903, by T. T. Behrens, E.E. This Acrseine butterfly 

 with its broad fulvous band crossing the fore-wing, and 

 white band crossing the hind-wing is evidently the primary 

 model of the particular variety of the semifulvescens, 

 Oberth., form of A. jolmstoni, shown in Fig. 2a. 



At the same time the latter exhibits a nearer approach 

 to the planemoides, Trim., $ form of Papilio dardanus^ 

 Brown., one of its co-mimics (compare Plate XX, 

 Fig. 4), than it bears to the central model of the grouj), 

 Planema poggei. 

 2a. Acreea johnstoni, form semifulvescens, Oberth., 9 • From 

 Taveta (about 2500 feet), British East Africa ; May 15, 

 1905, Rev. K. St. Aubyn Rogers. This form possesses a 

 pure white patch on the hind-wings, while the inner 

 area of the fore-wmgs is black instead of fulvous as in 

 typical semifulvescens (Plate XXI, Fig. 3a). This form 

 appears to mimic the planemoides female of Papilio 

 cJardanus more closely than any other member of the 

 large group clustered round Planema poggei (compare 

 Plate X of the present volume, accompanying Mr. S. A. 

 Neave's memoir). 



3. Planema latifasciata, E. M. Sharpe, (^ ; from Toro, W. 



Uganda (7-9000 ft.). November — December 1900: 

 Major Rattray. This Planema is the model for the 

 toruna form of johnstoni represented in the next figure. 

 3a. Acrsea johnstoni, form toruna, H. Grose-Smith, ^ ; from 

 the same locality and date as the preceding. The 

 mimetic likeness is strong in the deep rich brown of the 

 inner area of the fore-wings and basal region of hind- 

 wings in model and mimic, in the fulvous subajjical 

 band crossing the fore-wing and discal band crossing the 

 hind-wing, and finally in the dark ground colour external 

 to these striking markings. 



In all forms of Acriva johnstoni here represented (Figs. 

 la, lb, 2a, and 3a), the under-side exposed during 

 prolonged rest, when most of the fore-wing is hidden by 



