EYE-SPOTS OF THE WET SEASON 211 



therefore, that the eye-spots tend to be developed in the 

 active wet season individuals of many Satyr iuae and a few 

 Nyviphalinae as a special adaptation to meet the attacks 

 that are made upon them in the alert condition ; and 

 that eye-spots are withheld in the dry season brood 

 because they would be a danger in the periods of repose, 

 which are far more pronounced in this as compared with 

 the wet phase. 1 



The light thrown by recent investigations leads us confi- 

 dently to believe that the differences between the seasonal 

 forms — hitherto devoid of interpretation — have a meaning 

 and a value in the struggle for existence, and came into 

 being under the sway of Natural Selection. 



A new Interpretation of an old example of Mimicry in 



Butterflies. 



In the short time that remains I can only say a few 

 words about the recent growth of the theory of mimicry 

 which we owe to Fritz Miiller, and its gradual encroach- 

 ment upon the area formerly held by the theory of 

 H. W. Bates. This latter was not, as has been generally 

 supposed, originated by Bates during his years of obser- 

 vation in the valley of the Amazon. It arose in his mind 

 after his return home, when he came to examine his 

 collection and to reflect upon his experiences. His theory, 

 published in 1862, 2 is so well known that it is unnecessary 

 to do more than direct attention to the essential point, 

 that the mimics are supposed to be hard-pressed and 

 palatable insects which gain advantage from their close 

 resemblance to abundant, distasteful, conspicuous species. 

 Bates did not fail to see that these common, unpalatable 

 models certainly mimic each other, but the fact could 

 not be explained on his hypothesis ; and although he 

 mentioned the fact, no example finds a place in the 

 beautiful coloured figures of his historic memoir. Had 

 they been thus illustrated, I venture to think that his theory 

 would never have received the general support which has 

 been accorded to it ; for it would have been at once 



1 See Ann. Soc. Ent. France, vol. lxxii, 1903, p. 407. 



2 Trans. Linn. Soc, Lond., vol. xxiii, p. 495. 



P 2 



