334 Difficulties of Darwinism. [July, 
one of them before, he will from these characteristics 
suspect their origin. Now in this there is, to a certain 
point, nothing difficult to explain in accordance with the 
doctrine of Descent. Isolate two countries so that the 
animals and plants of each are perfe¢tly excluded from 
the other, then, if species do undergo any variation in 
course of ages, we may naturally expect that the Faune 
and Flore of the two regions will differ respectively from 
each other, and that the more decidedly the longer and 
the more complete has been their separation. As Mr. 
Wallace tersely puts the matter, ‘‘the individuality in the 
productions of a country is the measure of the time of its 
isolation.” But here arises a difficulty; the variation in 
each zoological or botanical district is apt to take some one 
specific direction. Thus there are in America, if we 
remember rightly, some thirty vegetable species which all 
differ from their nearest representatives on the eastern side 
of the Atlantic in one and the same manner. Mr. Wallace 
remarks in the butterflies of Celebes, as compared with 
those of the adjacent islands, a peculiarity of outline. Their 
fore-wings are either strongly curved or bent near the base, 
or extremely elongated and hooked. Now the climate of 
Celebes differs very little, if at all, from that of Borneo on 
the west, or of the Moluccas on the east. It is difficult in 
the extreme to imagine any reason why butterflies with the 
peculiarities thus indicated should enjoy any advantage in © 
the struggle for existence in Celebes which they would not 
equally experience in the surrounding islands. How, then, 
can we conceive these features due to Naturai Selection ? 
But there are local peculiarities, not merely in structure, 
but also in colour and design. ‘To what can these be due? 
It needs but little effort of the imagination to recognise in 
the patterns of Chinese butterflies, moths, and beetles, 
something of the stiff and grotesque character which strikes 
us in Chinese decorative art. 
Again, there is a difficulty in the distribution of zoological 
forms. Take those coleopterous groups which are most 
closely and dire¢tly dependent upon the vegetable kingdom, 
such as the Buprestide, Cetoniade, Dynastide, Curcu- 
lionidze, and Longicornes. We might naturally expect that 
in every tropical region where there is a profuse, luxuriant, 
and highly varied vegetable life, especially in the form of 
large trees, there the development of these groups would be 
mainly equal and similar. Yet nothing can be farther from 
the truth. There are decaying trees and rich vegetable 
mould in Africa, in India, and the Malay Archipelago. Yet 
