( 84 



II. Pseudacraea euiytus hobleyi, its forms and its models 

 on the islands of L. Victoria, and the bearing of the 

 facts on the explanation of tnimicry by Natural 

 Selection. By G. D. Hale Carpenter, M.B.E., 

 D.M., F.L.S.;F.E.S., F.Z.S., Uganda Medical Service. 



[lluad November 5tli, 1919.] 



Plates II, III. 



Forms of Pseudacraea eurytus hobleyi and its models were 

 the subject of a paper which was communicated to the 

 Society in November 1913, and was pubUshed in these 

 Transactions, March 31, 1914, pp. 60G-645. 



The object of the paper was to show that with com- 

 parative scarcity of models on the islands, mimics which 

 do not maintain the typically close resemblance are not 

 destroyed by the action of natural selection (working, 

 presumably, through vertebrate enemies), but are pre- 

 served ; while in other places such as Entebbe on the 

 mainland where models are more numerous than mimics 

 the latter are kept true to type. 



The explanation of the great number of varieties on the 

 islands as compared with the mainland was first suggested 

 to me by Prof. Poulton, as a result of a collection made 

 on Damba island in 1911, which was described in Proc. 

 Ent. Soc. 1911, pp. xci-xcv; 1912, pp. xxii-xxiii. Some 

 of them were figured on PI. xxxvi in the above-mentioned 

 paper in 1914. 



When I returned to the islands at the beginning of 1914 

 I went to a different group (see map), lying south of 

 Entebbe and about twenty-five miles from it. Camp was 

 pitched on the west end of the north shore of Kome, and 

 the neighbouring small islands Bulago, Tavu, Ngamba, 

 and Kimmi were frequently visited. 



In August 1914 work was cut short by the call of active 

 service, and during the rest of that year and in 1915 I 

 was with troops on the Kagera river to the west of the 

 lake. I spent many months at Kakindu (about 31° 30' E., 

 1° 10' S.), where was a fine forest known as the Tero 

 forest, and here were obtained more specimens of the forms 

 of Pseudacraea eurytus and their models. 



TRANS. ENT. SOC. LOND. 1920. — PARTS I, II. (jULY) 



