II] BATESIAN AND MULLERIAN 11 



and in future leave such butterflies severely alone. 

 The more conspicuous the pattern the more readily 

 would it be noticed by the enemy, and so it would 

 be of advantage to the Ithomiine to possess as striking 

 a pattern as possible. Those butterflies shewing a 

 tendency to a more conspicuous pattern would be 

 more immune to the attacks of birds and so would 

 have a better chance of leaving progeny than those 

 with a less conspicuous pattern. In__t his way_ -vajri- 

 ationsin the direction of grea tCT conspicuousness would 

 be accumiil ated gradually by natur al_ selection, and 

 so"would be Jrm1t_up in the Tt,hnmiirLR_Jihft_st>fkiTig 

 wafning^oloration by which_it adyertisjes its disagree- 

 abte'properties. Sijckis- the Jrst step in the making 

 of SL mimicry case-^the builduig up through natural 

 selection of a conspicuous pattern. in an unpalatable 

 species by means, of jghi.ch it is enabled to advertise its 

 disagreeable properties- fijffectively and thereby secure 

 irpinunity from the attacks, of eneiDiies which are able 

 to_appreciate the -advertisement. Such patterns and 

 colours are said to be of a "warning" nature. The 

 existence of an unpalatable model in considerable 

 numbers is the first step in the production of a mimetic 

 resemblance through the agency of natural selection. 



We come back now to our Piefiiie which must 

 be assumed to shew the general characters and color- 

 ation of the family of whites to which they belong 

 (cf. PI. X, fig. 1). Theoretically they are not specially 

 protected by nauseous properties from enemies and 

 hence their conspicuous white coloration renders 



