Darwin- Wallace Celebration. 73 



CENTRE TABLE. 



Problems of Evolution illustrated by Insects from the 

 Hope Collections in the Oxford University Museum. 



i. Mimicry in New World Papilionidce. 



Exhibited by the HOPE PROFESSOR OF ZOOLOGY 

 and Mr. J. C. MOULTON. 



The existence of superficial resemblances between the American 

 Papilios was pointed out by H. W. Bates in 1860 (Trans. Ent. Soc. 

 'Ser. II. vol. v. p. 335), and by A. R. Wallace in 1864 (Trans. Linn. 

 'Soc., vol. xxv. p. 10). 



These interesting examples of mimicry could, however, only be 

 adequately appreciated when the classification of the sub-family 

 Papilionidce had been put on a solid foundation by E. Haase 

 (Bibliotheca Zoologica, Stuttgart, Bd. iii. Heft 8, 1891-3) following 

 the lines suggested by Horsfield in 1857 (Cat. Lep. Ins. Mus. E. I. 

 Comp.). A full and detailed treatment of the subject has now 

 been rendered possible as a result of Rothschild and Jordan's 

 masterly revision (Nov. Zool. xiii. 1906, p. 411). 



ii. 



A. The Transition between species of Butterflies usually considered 



to be distinct. 



(1) Three forms of the genus Catopsilia, viz., C. crocale Cram., 

 C. pomona Fabr., and C. catilla Cram., were originally described as 

 distinct species, and are still usually so considered. The exhibit 

 shows that a perfect gradation exists between the typical forms of 

 C. crocale on the one hand and of C. catilla on the other, C. pomona 

 occupying an intermediate position between the two. 



(2) A similar transitional series connects two species of Mylothris, 

 alwajs hitherto treated as distinct, viz., M. chloris Fabr. and M. 

 agathina Cram. 



B. Sexual Dimorphism in Butterflies, associated with special pro- 



tection for the Female. 



Attention has been drawn by Dr. A. E. Wallace to tho fact that 

 in cases where the sexes differ in aspect, the female is usually the 



