( xlvii ) 



" The ' eccentric ' appearance is due to the margin of the 

 opposite wing appearing and disappearing, much as one disc 

 of a pair of eccentrics does behind the other. It is most 

 remarkable as being the only case I can call to mind of the 

 wings of opposite sides moving asymmetrically. Wings of 

 opposite sides in other cases move in an identical manner." 



■• I certainly associate the movements with rest in a warm 

 sun, but I don't think a flower is essential. After a short 

 flight the butterfly settles for some seconds, hardly minutes, 

 apparently really for a rest, not for basking, makes these 

 movements whilst resting, and then goes off. The rest is a 

 brief interval between flights, not a rest for the night or when 

 the sun is obscured." 



Although as a rule the eccentric movements were pei formed 

 with the wings nearly or quite closed, Prof. Poulton felt sure 

 he had seen them with the wings partially expanded so that 

 the upper surface was distinctly visible, and he remembered 

 Dr. Chapman suggesting, at a meeting of the Entomological 

 Society many years ago, that these movements, when made 

 by the males of some of our common species, perhaps pro- 

 moted the resemblance to a blue flower slightly twisting and 

 untwisting on its stalk in the breeze. 



The question arose as to whether the movements now ob- 

 served in tailless Lycaenids had persisted from some ancestral 

 time when tails were present — a view adopted in ''Colours of 

 Animals," pp. 208, 209. Prof. Poulton still thought that this 

 was the most probable interpretation in view of the preva- 

 lence of tails throughout the Lycaeninae of nearly all groups, 

 and the fact that the associated variations in the nervous 

 and muscular systems were n every way likely to persist 

 longer than variations in colour and pattern, and in such 

 structural features as the tails and lobes. If this view be 

 correct the eccentric movements of the non-tailed Lycaeninae 

 had some secondary meaning, probably directing attention 

 to the conspicuous marginal pattern of the hind-wing under 

 surface which is often strongly emphasised and often exhibits 

 one or more eye-spots in the region of the tail even when the 

 tail itself is wanting; when the wings are open perhaps 

 having the meaning tentatively suggested by Dr. Chapman. 



