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XIII. Mimetic Attraction. By Frederick A. Dixey, 

 MA., M.D., F.E.S., Fellow of Wadham College, 

 Oxford. 



[Read May 5th, 1897.] 



Plate VII, 



In a former contribution* to the Transactions of tliis 

 Society, I endeavoured to trace, by means of actual 

 examples, the successive steps through which a complicated 

 and practically perfect mimetic pattern could be evolved 

 in simple and easy stages from a form presenting merely 

 the ordinary aspect of its own genus. In the present 

 paper I propose to enter somewhat further into the 

 subject of mimetic change, and in the first place to show 

 how the process of gradual assimilation, starting from 

 one given point, may take not one direction only, but 

 several divergent paths at the same time ; in other 

 words, how the members of a single group may assume 

 several different mimetic developments, each one corres- 

 ponding to a distinct model, but all derived by easy 

 stages from the same original form. 



In the paper just referred to it was shown that a very 

 complete transition could be demonstrated, by means of 

 closely-allied and still existing species, between an 

 ordinary Fieris such as P. -pludoe, presenting only the 

 usual features of its genus, and a form of such widely 

 different aspect as Mylothris pyrrha $ ; the latter beiug 

 a nearly exact copy of Heliconius numata. But although 

 these facts are sufficiently striking, it is perhaps still 

 more remarkable that from the same or closely allied and 

 very similar forms of typical Pierine aspect, at least four 

 other lines can be traced, each showing almost as perfect 

 a transition as that from P. i:)lialoe to M. pyrylia, and 

 each leading up to a presumably distasteful model ; these 

 models being in appearance entirely different from M. 

 numata and from each other. 



* " On the Relation of Mimetic Patterns to the Original Form," 

 Trans. Ent. Soc. Lond. 1896, pp. 65-79, pis. III.-V. 



TRANS. EKT. SOC. LOND. 1897. PART III. (sEPT.) 



