258 PSEUDACRAEA EURYTUS 



the forms are beginning to run into each other and also 

 to assume entirely different proportions from those of the 

 mainland. It is most interesting and indeed exciting." 



Early in 1912 I moved camp to the north-east corner 

 of Bugalla Island, the largest of the Sesse archipelago in 

 the north-west corner of the Lake. The north-west 

 promontory of this island almost touches the mainland 

 coastline at the port of Bukakata (see map). 



It very soon became apparent that all the combinations 

 which were of so great interest at Entebbe and on Damba 

 Island were present here, and on March 16, 1912, Pro- 

 fessor Poulton wrote : 



" I am very glad that Sesse is turning out to be so 

 interesting, and I quite think now that it will be even 

 more interesting to compare these two groups of islands 

 together rather than to get evidence from only one. You 

 will realize the utmost importance of catching all the 

 models and mimics you can secure on given days without 

 any selection, so that we can estimate the proportions 

 of models and mimics and see whether, as in Damba, 

 the mimics are relatively far more abundant than on the 

 mainland, and whether, as also in Damba, the inter- 

 mediates are specially prevalent. 



If the results in Damba are supported by a large col- 

 lection on Sesse, I think the matter will really be estab- 

 lished, and will constitute the strongest argument I 

 know for the origin and maintenance of mimicry by 

 natural selection ; for directly the models are reduced 

 the mimics begin to run into each other. I think, in 

 your case, when you are necessarily pressed with other 

 work, that it would be best to concentrate attention on 

 the most important problems, and those certainly are 

 the proportions of models and mimics and the compo- 

 sition of the mimetic Pseudacraea group, and breeding 

 the latter to prove that they are all one." 



April 6, 1912. — " How splendid that the problem is 



