xm VARIATION AND EVOLUTION 145 



different family of the Nymphalidae, to which there is no 

 evidence for assigning the disagreeable properties of the 

 Danaines. Now the different species of Euralia show re- 

 markably close resemblances to the species of Amauris, 

 which are found flying in the same region, and it is sup- 

 posed that by " mimicking" the unpalatable forms they 

 impose upon their enemies and thereby acquire immunity 

 from attack. The point at issue is the way in which this 

 seemingly purposeful resemblance has been brought 

 about. 



One of the species of Euralia occurs in two very dis- 

 tinct forms (PL VI.) , which were previously regarded as 

 separate species under the names E. wahlbergi and E. 

 mima. These two forms respectively resemble Amauris 

 dominicanus and A. echeria. For purposes of argument 

 we will assume A. echeria to be the more recent form of 

 the two. On the modern Darwinian view certain in- 

 dividuals of A. dominicanus gradually diverged from the 

 dominicanus type and eventually reached the echeria type, 

 though why this should have happened does not appear 

 to be clear. At the same time those specimens which 

 tended to vary in the direction of A. echeria in places 

 where this species was more abundant than A . dominicanus 

 were encouraged by natural selection, and under its 

 guiding hand the form mima eventually arose from wakl- 



According to Mendelian views, on the other hand, 



