Chap. VI. ORIGIN OF SPECIES. 265 



to its former shape when brought by natural redistribu- 

 tion into contact with it.* 



* If this explanation of the derivation of Heliconius Thelxiope be true, 

 the origination by natural process of a host of now distinct allied species 

 of this genus, as well as, in fact, all other genera containing numerous 

 closely related species, will have to be admitted. A species allied to H. 

 Thelxiope, namely, H. Vesta, seems to have been derived also from H. 

 Melpomene, for amongst the numerous varieties already mentioned are 

 many examples intermediate between the two. There is this difference, 

 however, between H. Thelxiope and H. Vesta : the former is confined 

 in its range to the Amazons valley, whilst H. Vesta extends beyond 

 this region over Guiana and the central valleys of the Andes ; it seems, 

 therefore, to have acquired a power of adajjtation to a much wider 

 diversity of local conditions. Insects seem to be well adapted to furnish 

 data in illustration of this interesting but difficult subject. This arises 

 chiefly from the ease with which ample suites of specimens can be 

 obtained for comparison from many points in the areas of distribution, 

 both of species and varieties. It is scarcely necessary to add that the 

 conclusions thus arrived at will apply to all organic beings. 



