(By) 
XIII. Mimetic Attraction. By Freperick A. Drxey, 
M.A., M.D, F.E.S., Fellow of Wadham College, 
Oxford. 
[Read May 5th, 1897.] 
Pirate VII. 
In a former contribution* to the Transactions of this 
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. 
Jn the paper just referred to it was shown that a very 
complete transition could be demonstrated, by means cof 
closely-allied and still existing species, between an 
ordinary Pieris such as P. phaloe, presenting only the 
usual features of its genus, and a form of such widely 
different aspect as Mylothris pyrrha 2 ; the latter being 
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. phaloe to M. pyrrha, and 
each leading up to a presumably distasteful model; these 
models being in appearance entirely different from H. 
numata and from each other. 
* © On the Relation of Mimetic Patterns to the Original Form,” 
Trans. Ent. Soc. Lond. 1896, pp. 65-79, pls. ILI.—V. 
TRANS. ENT. SOC. LOND. 1897.—PparRT II. (SEP'.) 
