212 CHARLES DARWIN. 



and Thyridia." This paper, although it did not 

 attract sufficient attention at the time, was of the 

 highest importance in relation to the theory of 

 mimicry, as Meldola at once perceived. 



Bates in his epoch-making paper in the Transac- 

 tions of the Linnean Society (Vol. XXIII. 1862) had 

 founded the theory of mimicry. Those rarer forms 

 which have diverged from their near allies and, in 

 superficial appearance, approached some distantly 

 related, but abundant, species inhabiting the same 

 tract have been, according to Bates's theory, benefit- 

 ing themselves in the struggle for existence. The 

 mimicked species are, he suggested, abundant because 

 they possess some special means of protection, such as 

 an unpleasant taste or smell, and they have an unpleas- 

 ant reputation which greatly aids them in the struggle 

 for life ; while the mimicking species, by their super- 

 ficial resemblance, are enabled to live upon that 

 reputation without possessing the special means 

 of defence. 



Certain facts well-known to Bates, and brought 

 forward in his paper, were not explicable by this 

 theory, viz. the resemblance that often exists between 

 the abundant and specially protected species them- 

 selves. Although a few tentative suggestions were 

 made, such as the production of a common appearance 

 by similarity of climate, or food, etc., these facts 

 remained an unexplained mystery until this paper ot 

 Fritz Miiller's in the May number of Kosmos. He 

 there suggests that the mutual resemblance between 



