( viii ) 



possibility of parallel variation ought not to be excluded. To 

 take the case of H. thelxiope and H. vesta, the "typical" 

 forms might be assumed, ex hypothesi, to be the most ancestral, 

 and to have acquired their common resemblance by conver- 

 gence ; but from these forms were derived, as the series 

 exhibited showed, a number of paired varieties which were 

 progressively modified in relation to their distribution. There 

 was nothing to show that either species had been influenced 

 in its variation by the other, and that it would not have 

 followed the same course if it had been isolated. And it was 

 conceivable that the causes, in most cases unknown, which 

 brought about modifications in the colour and markings of a 

 species in association with its geographical -range, might have 

 produced identical results in two species of the same genus, 

 with a common facies, under common conditions. 



Prof. PouLTON : He congratulated Dr. Dixey on his care- 

 ful work, and on the deep interest of the results he had 

 obtained. It was a great source of satisfaction to him that 

 this research had been conducted in the Hope Department of 

 the Oxford University Museum. 



He then exhibited a further series of neotropical butterflies 

 from the Godman-Salvin collection, illustrating the various 

 members of the group which had been formed round Mctlwna 

 confusa, Butl., and Thyridia jysidii, L. ; the best known moths 

 (of the genera Castnia and Hijelosia) which fell into the group, 

 were supplied by specimens from the Hope collection. This 

 group which, as regards most of its members, had been 

 originally described by H. W. Bates, occupied a very wide 

 geographical area, and was of special interest, not only on 

 account of the number of forms which entered into it, but 

 also because of the perfection of the resemblance. 



Further, he exhibited the smaller group which converges 

 SLYonndltmialamira, Latr.,and species of Ohjras, Thyridia, etc., 

 the specimens being selected from the Godman-Salvin collec- 

 tion ; he also showed several groups characteristic of Honduras, 

 Surinam, Eastern Brazil, etc., the specimens having been 

 recently acquired by the Hope collection for the purpose of 

 illustrating the principles of Warning Colours and Mimicry. 

 Many of these specimens possessed the special interest that 



