41 8 MY LIFE [Chap. 



and wishing to introduce a paragraph as to the division of 

 the Malay Archipelago into two regions, and the relation of 

 this division to the races of man, and also as to the probable 

 rate of change of insects, he asked me for a short statement 

 of my conclusions on these subjects. On the latter point I 

 wrote : — 



"As regards insects changing rapidly, I see nothing 



improbable in it, because, though in a totally different way, 



they are as highly specialized as are birds or mammals, and, 



through the transformations they undergo, have still more 



complicated relations with the organic and inorganic worlds. 



For instance, they are subject to different kinds of danger 



in their larva, pupa, and imago state ; they have different 



enemies and special means of protection in each of these 



states, and changes of climate may probably affect them 



differently in each state. We may therefore expect very 



slight changes in the proportions of other animals, in physical 



geography, or in climate, to produce an immediate change in 



their numbers, and often in their organization. The fact that 



they do change rapidly is, I think, shown by the large number 



of peculiar species of insects in Madeira as compared with 



the birds and plants ; the same thing occurs in Corsica, where 



there are many peculiar species of insects ; also, we see the 



very limited of range of many insects as found by Bates and 



myself. Again, your rule of the slow change of mollusca 



applies to aquatic species only. The land-shells, I presume, 



change much more rapidly ; or why are almost every species 



in Madeira and in each of the West Indian islands peculiar ? 



Being terrestrial, they are affected as insects are by physical 



changes, and more still by organic changes. Such changes 



are certainly much slower in the sea." 



Later on, in May, after reading my article on " The Races 

 of Man and Natural Selection," which Darwin thought so 

 highly of, though at the same time he was quite distressed 

 at my conclusion that natural selection could not have done 

 it all, Sir Charles objected (May 22, 1864) — very naturally 

 for a geologist, and for one who had so recently become a 

 convert to Darwin's views — that my suggestion of man's 



