( 48 ) 



of the fact that the Hawaiian Colour-groups were especially 

 characteristic of the forests. The difference between the 

 development of mimetic patterns in Lepidoptera of the open 

 country and those of the forest areas of Africa was extremely 

 striking, and Professor Poulton had already been driven to 

 the only hypothesis which Dr. Perkins could suggest as a 

 possible explanation of the facts, viz. differences between the 

 insect enemies in the two types of country (see pp. 1-liii). 



The only point in which his experience differed from that of 

 Dr. Perkins was in the relative prevalence of variability and 

 of mimicry in the two sexes of insects. 



Dr. Perkins was by no means convinced of the validity of 

 the Miillerian interpretation, and felt many difficulties, but, at 

 any rate, he stated that he was unable to suggest any other 

 explanation, and he had definitely abandoned the climatic 

 solution, which many have found so alluring. 



Prof. Poulton said, in conclusion, thai he wished to make 

 one remark on the bearing of the whole body of facts recorded 

 in Dr. Perkins's memoir. He was aware that it was dangerous 

 to limit the possibilities of future discovery, and to argue 

 from the unknown to the non-existent. He realised that 

 nearly every great discovery in liiology revealed something 

 that lay close at hand although it was unseen. But, allowing 

 for all this, he ventured to affirm that, if, in these little 

 islands— closely examined as they had been for so long a 



[lxv 

 period by so keen and discriminating a naturalist and one who 

 had shown a life-long devotion to the Aculeates, not only as 

 specimens, hut as living beings nothing except the Miillerian 

 principle could be suggested as the cause of the Colour-groups, 

 then it was far more reasonable to conclude that the in- 

 sufficiency of the evidence was due to changed conditions 

 brought about by man,* than to suppose that there existed in 

 these restricted areas some set of causes hitherto unsuspected 

 and unknown. 



* Dr. Perkins describes the immense changes thai have taken place in 

 the bird fauna within his nun memory, and argues that, it' the Colour- 

 groups were formed by the Mullerian principle, it was under conditions 

 that do not now exist. 



