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TMR TLACl-. OF M1M1CR\ 



the aim of nature could not be ' simple conspicuousness 

 alone. There is the dani^er of special enemies, and the 

 dani^er of special 1) hungry enemies ; and it must be 

 freelv admitted that conspicuousness beyond what is 

 necessar\' for warninij' an attackiiiLT enemy would be 

 a danger. Mr. Thayer states that iridescence tends to 

 render colours less consjjicuous, and we certainly observe 

 that a uniform black appearance unrelieved b)' pattern is 

 continually accompanied b)- iridescence or structural 

 surHice colours of some kind. In view of Mr. Thayer's 

 suggestion, it becomes probable that dead black would 

 be too conspicuous for many a well-armed Aculeate or 

 nauseous Euploca, and that it is therefore modified so 

 that it obtrudes less upon the distant view of enemies 

 that ' mean business '.^ 



Naturalists have used the term 'conspicuous' relativel)-, 

 and furthermore, in using it, have taken into account the 

 habits, movements, modes of displa)-, t\:c., which ma\- 

 be of even more importance than the colouring itself. 

 The Ithomiine and convergent Heliconine butterflies of 

 tropical America are no doubt far from possessing an 

 ' intrinsically revealing coloration ' such as Mr. Thayer 

 describes ; iDut it is equally true that they fall into an 

 entirel}- different category from that which includes the 

 Cr) ptic species, with undersides resembling leaves, bark, 

 &c. Mr. Thayer suggests that the)- resemble flowers, 

 and the surroundings of ilowers, and that their extra- 

 ordinar)- likeness to each other may be incidentally due 

 to their resemblinir the same kind of flower — in other 

 words may be S)ncr)ptic. The I>ritish Guiana associa- 

 tion of I tlioniiinac, Hclico)iinae, &c. (see pp. 331-3) has 

 been studied in its native haunts far more completely 

 than any other. Mr. \\\ J. Kaye, who has devoted 

 special and prolonged attention to them, states that these 

 black, 'cow-red, and chrome-yellow' butterflies, as they 

 are precisely described by Mr. Thayer, frequent ' the 

 white flowers of the plant Eupatoriuvi macrophylluni ' } 

 There is no evidence of Cryptic Resemblance to flowers 



' Trans. Ent. Soc, Loud., 1903, p. 575. 

 '^ Trans, Ent. Soc, Lond., 1906, p. 412. 



