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so that the insect lays a green egg which hatches into a 
green grub. In other cases it is reasonable to suppose 
that changed conditions have produced a direct effect, 
though it may not be possible to prove that this is so. 
Take, for example, the case of the eland :— 
“A curious point in the always singular freaks of the geographical 
distribution of animals is to be found in connection with the eland. 
The eland of the Cape Colony, Orange Free State, Transvaal, 
Namaqualand, and Demaraland, in the old days, and the eland of 
the Kalahari, at the present time, were and are always entirely devoid 
of markings, the body-colouring varying from a dun or fawn in the 
younger beasts to a bluish buff in the old animals. In Mashunaland 
and Portuguese South-eastern Africa and beyond the Zambesi—in all 
parts of Africa where elands are to be found—they are met with, 
bearing invariably a number of white stripings across the body—very 
similar to the markings of the koodoo—and are marked also with a 
black patch on the outer side of the fore-arm, and a dark list running 
down the spine. These characteristic stripings are entirely wanting 
in the eland of South-western Africa, which from the rapid narrowing 
of its habitat and its constant persecution, is, as I have pointed out, 
likely not long hence to vanish altogether. That the absence of 
stripings has accompanied a more desert and waterless, more 
temperate and less tropical habitat, is a plain fact enough. And that 
the stripings appear in all elands throughout the more tropical parts 
of Africa is also perfectly apparent. To explain the variation is a 
much more difficult matter. Possibly heat and moisture have some 
thing to do with it. This, however, is a difficult and a thorny subject, 
and even Darwin himself was oftentimes puzzled to account for the 
capricious nature of the markings and stripings of animals.”— 
(H. A. Bryden. Chambers' Journal, vol. xi., jth series, p. 674.— 
The Vanishing Eland.) 
No doubt the markings are capricious from the point of 
view of Natural Selection, but if we knew all the effects of 
external conditions and of internal organisation, we should 
see that every mark had its obvious cause. 
What are we to understand Mr. Wallace to mean when 
he tells us that having found, as he believes, that protective 
colouring can be produced by Natural Selection, we may 
rest content and need seek no other cause for the phe 
nomenon ? Remembering that this is a case in which the 
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