OBJECTIONS TO THE THEORY OF MIMICRY 



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The late W. C. Hewitson was one of the first to record his lack of faith in these principles 

 We have already seen how impossible of belief he found Trimen's theory concerning the female 

 forms of P. dardanus, though probably few naturalists have ever given such a peculiarly 

 unscientific reason for their views. Hewitson's objections do not in fact demand serious 

 consideration, since, in common with many others who have criticized Darwin's theories, 

 he does not appear to have understood the principles in which he professed disbelief. Further 

 reference would be unnecessary were it not for the fact that in his ' Exotic Butterflies ' 

 there occurs a passage which reads as follows : ' May not all the imitators of these scented 

 aristocrats be simply votaries of fashion, aping the dress of their superiors, and, since the 

 females take the lead, " naturally selecting " those of the gayest colours.' It is worthy 

 of note that there is a suggestion in this passage which at first sight appears to be a kind 

 of dim perception of the idea of sexual selection, though it is doubtful whether this was the 

 writer's intention, and it more probably suggests a kind of conscious selection of certain 

 colours on the part of the females for their own adornment, a process which is no more credible 

 than that a man can ' by taking thought add one cubit to his stature ' . The late Dr. Fritz 

 Miiller was the first to advance the idea of sexual selection, the principle of the theory being 

 that the comparatively rare mimic, being surrounded by large numbers of the model, might 

 come to appreciate the colours which were thus so frequently displayed before it, and so 

 prefer, in pairing, to select individuals of its own species which by variation tended to 

 exhibit those colours in the highest degree. By this means the resemblance to the model 

 or dominant form would be increased and perpetuated. The suggestion was made in a letter 

 to Darwin in 1872. The latter considered the theory as rather too speculative, although 

 at the time he inclined to the idea that it was not as incredible as might at first sight appear.'- 

 Sexual selection is not, however, sufficient to account for many of the resemblances with 

 which we are now acquainted, such, for instance, as the polymorphic forms of P. dardanus ; 

 nor would this explanation have any weight in the case of the resemblance of a larva to a 

 snake, or that of the pupa of the Magpie moth to a wasp. 



In 1897 a most interesting discussion took place during the first two meetings of the 

 Entomological Society of London, when the subject of mimicry was dealt with by many 

 of the Fellows. The discussion followed the communication of Dr. Dixey's valuable paper 

 on ' Mimetic Attraction ', and the exhibition by Mr. Blandford of groups of butterflies 

 from the Neotropical region, such groups exhibiting what Mr. Blandford described as 

 ' homoeochromatism ', the term being used in order to express the phenomenon of what 

 is known as Miillerian resemblance, without implying any theoretical considerations as to 

 its origin. In explaining the exhibit, it was pointed out that some of the resemblances were 

 so close as to be of the nature of hypertely,^ and that the selective force could scarcely be 

 considered adequate to produce such perfection in minute details. In the case of many of 

 the resemblances it was pointed out that there was nothing to show that identical conditions 

 might not have brought about identical results in the matter of variation of colour patterns. 

 In this case the explanation suggested appears to have been that of parallel variation. 

 The remoteness of the possibility of two butterflies, or any two other creatures, arriving at the 

 same result by a process of parallel variation has only to be considered in order to be rejected. 

 If the influences which give rise to variation, and the controlling forces which select certain 



1 See ' Charles Darwin and the Theory of express the idea that certain resemblances such as 

 Natural Selection,' Poulton, London, igoi. those of the tegmina of leaf-like Orihopiera, were 



2 This term was proposed by B. von Wattenwyl so perfect in detail as to be beyond the limits of 

 (Verk. Zool. Bot. Ges. Wien., 1883, p. 248) to usefulness. 



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