64 THE STUDY OF ANIMAL LIFE CHAP. 



mimicry is rare, but it is well known that some harm- 

 less snakes mimic poisonous species. Thus, the very 

 poisonous coral-snakes (Elaps), which have very char- 

 acteristic markings, are mimicked in different localities 

 by several harmless forms. Similarly in regard to birds, 

 Mr. Wallace notices that the powerful " friar-birds ' 

 (Tropidorhynchus) of Malaya are mimicked by the weak 

 t nd timid orioles. ; In each of the great islands of the 

 Austro-Malayan region there is a distinct species of 

 Tropidorhynchus, and there is always along with it an 

 oriole that exactly mimics it." When the model is un- 

 palatable or repulsive or dangerous, and the mimic the 

 reverse, the mimicry is called Batesian. (after Mr. Bates), 

 but another kind of mimicry is known called Miillerian 

 (after Fritz Muller) where the mimic is as unpalatable 

 as the model. The theorv in this case is that the 



* 



mimicry serves as a mutual assurance, the members of 



J 



the ring being the safer by all having a livery which has 

 come to mean to their enemies <: Leave me alone." 

 That there may be mimetic resemblance between dis- 



to 



tinct forms there can be no doubt, and the value of the 

 resemblance has been verified ; but there is sometimes 

 a tendency to weaken the case by citing instances or 

 using terms which have been insufficiently criticised. 

 Thus the facts hardly justify us in saying that the larvae 

 of the Elephant Hawk Moth (Chcerocampa) " terrify their 

 enemies by the suggestion of a cobra-like serpent " ; or 

 that the cobra, which " inspires alarm by the large eye- 

 like ' spectacles ' upon the dilated hood, offers an appro- 

 priate model for the swollen anterior end of the cater- 

 pillar, with its terrifying markings." 



According to the Darwinian theory, varieties cropped 

 up among the mimicking animals which prospered by 

 being 1 somewhat like the mimicked, and in the course 



O 7 



of natural selection this resemblance was gradually in- 

 creased until it became dominant and, in many cases, 

 remarkably exact. 



10. " Masking " is one of the most interesting ways 

 in which animals strengthen their hold on life. It is best 

 illustrated on the sea-shore, where there is a keen struggle 



