( lviii ) 



Anthicidse (Anthicus, Formicomus, etc.), which resemble ants, 

 scarcely any instance of the mimicry of other orders is found 

 among the Heteromera. 



If we endeavour to give any explanation of Miillerian 

 mimicry, we are of course met by many objections. How did 

 it arise ? Is there enough ground to work upon 1 Are there 

 any factors besides Natural Selection, and if so what are they ? 

 We cannot, of course, in the present state of our knowledge, 

 give answers that will satisfy persistent objectors, but those 

 who have at all studied the subject do not see any particular 

 difficulty in recognising that in the keen struggle for existence 

 Natural Selection and Variation may in time weed down two 

 or more distasteful species until they resemble each other in 

 minute particulars. Mimicry is a progressive and continuous 

 process : it is playing a large part in the history of nature in 

 the present, as it has done in the past and will continue to do 

 in the future. In a letter which I received a short time ago 

 from Dr. Alfred Russel Wallace, after saying that the toll of 

 each insect exacted by insect-eaters is reduced exactly in pro- 

 portion as more and more species so nearly resemble each other 

 as to be apparently almost identical, he writes as follows : — 

 " Hence if any simple pattern of warning colour is acquired by 

 one protected species, there is a tendency for many other 

 species, both protected and non-protected, to acquire similar 

 colours and patterns (by variation and selection). Also 

 protective markings may be acquired in the same way, and 

 some very conspicuous markings, when the insect is in 

 motion, become highly protective when it is at rest in its 

 natural surroundings." The latter remark is very important : 

 we are too apt to forget the necessity of taking environment 

 into consideration. 



Dr. Wallace is further of opinion that the beginnings of 

 such peculiar markings are often due to the need for re- 

 cognition on " the first differentiation of species, and does not 

 doubt but that this acts with beetles as it certainly does with 

 higher animals" : such may be the case, but it hardly seems 

 probable. 



There are several points which I am afraid have been only 

 meagrely dealt with, and several others which I should like to 



