v] SOME CRITICISMS 57 



of the greater abundance of the mimic that in such 

 cases we are concerned with Mullerian mimicry, that 

 since both of the species concerned are distasteful 

 there is not, strictly speaking, either a mimic or a 

 model, and consequently the relative proportions have 

 not the significance that they possess where the 

 mimicry is of the simple Batesian type. It is, however, 

 very doubtful whether such an explanation is of any 

 value, for, as will appear later, there are grave objections 

 to accepting the current theory as to the way in which 

 a resemblance is established on Mullerian lines (cf. 

 pp. 72-74). 



(4) That the imitators differ from the bulk of their 

 allies. 



What importance we attach to this condition 

 must depend upon our interpretation of the word 

 "allies" — whether, for example, we use it for a small 

 group of closely connected species, for a genus, for 

 a group of genera, or in an even wider sense. Perhaps 

 an example will serve to make the difficulty more 

 clear. As already noticed, the S. American genus 

 Dismorphia belongs to the family of Pieridae or 

 " whites." Also certain species of Dismorphia bear a 

 close resemblance to certain species of Ithomiines, 

 a noteworthy example being D. praxinoe and Mecha- 

 nitis saturata (PL X, figs. 3 and 7), in which the 

 pattern, colour, and shape of the two species are 

 all far removed from what is usually understood by 

 a "white." It must not be forgotten, however, that 

 these matters are generally discussed by European 



