Extinction, of Organic Beings. 478 



similar climates seem in most cases to produce rather a 

 strong similarity, than an absolute identity of species. Thus 

 in the lofty ranges of the Himalaya, some climates may be 

 found (at least if we may judge of climates by their pro- 

 ducts) approaching to those of the lowland tracts of Europe. 

 Here ranging through the hills from an elevation of three 

 thousand feet to that of twelve, and probably thirteen thou- 

 sand feet above the sea, are found in numbers, the Tortoise- 

 shell/ 15 Brimstone, (2) and Swallow-tail (3) Butterflies, identical 

 with those of Europe ; the larva of the former still feeding 

 on a species of nettle (Urtica.) 



In company with these may also be seen various species 

 of the white butterflies found in Europe, as well as the 

 "painted lady," (Cynthia cardui) ; the last named species 

 is likewise found at Candahar, in company with Pieris era- 

 tcegi, or the black -veined white butterfly, and Pontia rapes, 

 the small cabbage butterfly. 



These species are all identical with those of Europe, and 

 doubtless there are many more besides, but still this does 

 not by any means prove that the climates are identical with 

 those of Europe, but only that these species are so consti- 

 tuted as to be able to live and thrive in various tempera- 

 tures ; for if the climates were the same, then might we 

 seek in Europe for the many species which are now ap- 

 parently peculiar to the Himalaya. 



The animals common to both regions therefore, are few 

 in comparison of those which are peculiar to either; and 

 thus, although at first the identity of some species, and the 

 strong similarity of others, might lead one to agree with 

 some writers that species have no real existence in nature, 

 but have descended from a common source, and become 

 modified by climate, yet the absolute distinctness of others 

 peculiar only to certain regions, and often even to particular 



(!) Vanessa urticae. (2) Gonepteryx rhamni. 



( 3 ) Papilio machaon. 



