104 A NATURALIST IN BORNEO 



has, like the Red-Headed Krait, a scarlet head and 

 tail, though otherwise it is not at all like the poisonous 

 species. If these are examples of mimicry, the mimicry 

 is very far from being exact, and it may well be asked 

 how such imperfect resemblance can be of any value 

 to these defenceless snakes. It is perhaps a legitimate 

 answer that snake-enemies have, through the action of 

 natural selection, learnt instinctively to regard scarlet 

 as an advertisement of poisonous properties, just as it is 

 almost certain that animals and birds avoid poisonous 

 plants and fruits, not from experience of the ill-effects 

 of eating these, but from an instinct called into being 

 by selection. If a patch of scarlet colour inspires 

 dread or even only caution in a snake-destroying 

 animal, the display of this colour by a non-poisonous 

 snake will suffice to scare away a certain number of 

 its enemies. Theories of this nature, however, require 

 a large body of experimental evidence to support them 

 before they can meet with wide acceptance, and such 

 evidence is unfortunately entirely lacking in the in- 

 stances just quoted. 



Note, p. 92. Malayan Cobra. The Ringhals, or Spugh-slang 

 ("Spitting Snake"), Sepedon hcemachates, of South Africa, has 

 the same habit. The discharged saliva is very acrid and a 

 powerful irritant. This snake is nearly related to the Cobra. 

 H. B. 



See The Snakes of South Africa, by F. W. Fitzsimons, F.Z.S., 

 1912, pp. 183-91 ; pp. 488-9. G. B. L. 



