134 MENDELISM CHAP. 



genus Euralia belonging to the entirely 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 remarkably close resemblances to the species 

 of Amauris, which are found flying in the same 

 region, and it is supposed 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 

 distinct forms (PI. VI.) which were previously re- 

 garded as separate species under the names E. 

 wahlbergi and E, mima. These two forms respec- 

 tively 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 individuals 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 eventu- 

 ally arose from wahlbergi. 



According to Mendelian views, on the other hand, 

 A. echeria arose suddenly from A. dominicanus (or 

 vice versa), and similarly mima arose suddenly from 

 wahlbergi. If mima occurred where A. echeria was 

 common and A. dominicanus was rare, its resemblance 



