The Struggle for Existence 147 



by Birds because they have a reputation for unpalatability, or be- 

 cause they are able to sting, the mimickers survive although they 

 are palatable and stingless. They succeed, not through any virtue 

 of their own, but because of their resemblance to the mimicked, 

 for whom they are mistaken. There are many cases of mimetic 

 resemblance so striking and so subtle that it seems impossible to 

 doubt that the thing works ; there are other cases which are rather 

 far-fetched, and may be somewhat of the nature of coincidences. 

 Thus although Mr. Bates tells us that he repeatedly shot hum- 

 ming-bird moths in mistake for humming-birds, we cannot think 

 that this is a good illustration of mimicry. What is needed for 

 many cases is what is forthcoming for some, namely, experi- 

 mental evidence, e.g. that the unpalatable mimicked butterflies 

 are left in relative peace while similar palatable butterflies are 

 persecuted. It is also necessary to show that the mimickers do 

 actually consort with the mimicked. Some beetles and moths are 

 curiously wasplike, which may be a great advantage ; the common 

 drone-fly is superficially like a small bee; some harmless snakes 

 are very like poisonous species; and Mr. Wallace maintained 

 that the powerful "friar-birds" of the Far East are mimicked by 

 the weak and timid orioles. When the model is unpalatable or 

 repulsive or dangerous, and the mimic the reverse, the mimicry 

 is called "Batesian" (after Mr. Bates), but there is another kind 

 of mimicry called Miillerian( after Fritz Miiller) where the mimic 

 is also unpalatable. The theory in this case is that the mimicry 

 serves as mutual assurance, the members of the ring getting on 

 better by consistently presenting the same appearance, which has 

 come to mean to possible enemies a signal, Noli me tangere 

 ("Leave me alone"). There is nothing out of the ques- 

 tion in this theory, but it requires to be taken in a 

 critical spirit. It leads us to think of "warning colours," 

 which are the very opposite of the disguises which we are 

 now studying. Some creatures like skunks, magpies, coral- 

 snakes, cobras, brightly coloured tree-frogs are obtrusive rather 



