PROTECTIVE MIMICRY 921 



principle especially supported and extended by Wal- 

 lace; also greatly supported by Trimen, Belt, and 

 many others. 



2. The tendency for the species in each specially 

 protected group of butterflies to resemble each other 

 (by convergence or arrested diyergence) more closely 

 than those in other groups not similarly protected, 

 thus suffering a smaller amount of destruction while 

 their enemies are being educated to avoid them ; sug- 

 gested by Meldola (' Ann. and Mag. Nat. Hist.' Dec. 

 1882) as an extension of the principle discovered by 

 Fritz Miiller and described in the next paragraph. 



3. The tendency for the members of distantly re- 

 lated groups of specially protected butterflies to resemble 

 each other, thus gaining the advantages described 

 above : discovered by Fritz Miiller (' Proc. Ent. Soc. 

 Lond.' 1879, p. xx.). The fact of the resemblance was 

 first observed by Bates {loc. cit.). 



4. An extension of the same principle to all the 

 groups of such specially protected animals : in these 

 the same colours and patterns occur again and again, 

 and advantage is gained by the fact that the types of 

 appearance are those which produce most effect upon 

 the sight of an enemj^, as well as by the fact that only 

 a few different types have to be learnt. Certain types 

 of colour and pattern are eminently advantageous for 

 animals in which the special protection is imperfect, 

 because they are so thoroughly advertised by other 

 animals in which the protection is complete and 



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