256 PSEUDACRAEA EURYTUS 



tion that it was difficult to assign specimens to any 

 particular form, for a single specimen often appeared to 

 be transitional between terra, hohleyi and obscura. The 

 model species of Planema were extremely scarce on 

 Damba, and this point proved to be of great significance. 



A letter from Professor Poulton, dated October 30, 1911, 

 referring to the arrival at Oxford of the first consignment 

 of these intermediate Pseudacraeas, said : " They looked 

 most interesting, and perhaps here your island forms 

 will be different and throw light on the polymorphism 

 of this set of forms." 



November 9, 1911. — " You have the Pseudacraeas abun- 

 dantly evidently, and it is of the utmost importance 

 to breed them from known parents. They tend to be 

 far more intermediate than on the mainland. I suspect 

 that selection of them is somewhat relaxed on the island, 

 and they at once tend to mix. You have terra and 

 hohleyi ? (I've not seen <? yet) and another form, 

 obscura, and transitions of the most beautiful kind 

 between obscura and terra, and between obscura and 

 hohleyi ? . I've only seen now among your specimens 

 the models of hohleyi {Planema macarista 3' and ? and 

 PL poggei), but no models as yet of the other two {terra 

 and obscura). Now if these models are rare or absent 

 perhaps we have the cause of the varieties of obscura 

 and terra, viz. a consequence of freedom from rigid 

 selection. It is an exciting problem, and you are 

 evidently in a most interesting locality." 



November 12, 1911. — "This is the exciting thing; 

 there is no doubt that the Pseudacraeas tend to lose their 

 distinctness in the absence, or rarity, of their models. 

 It is most interesting and entirely supports Dr. Jordan's 

 views. I cannot tell you how pleased I am." 



These specimens from Damba Island were exhibited 

 at a meeting of the Entomological Society of London on 

 December 6, 1911, by Professor Poulton, who said: 



