202 CHARLES DARWIN. 



" I enclose a letter from Fritz Miiller which I think is well 

 worth reading, and which please to return to me. 



" Yo u will see hg Jiajffl j much stress on the difficu lty of 

 seve r aTremotely allied form s all imitating s ome one specie^ . 

 Mr. Wallace did not think that there was so much weightin 

 this objection as I do. It is, h owever, possible that a few 

 species in widel y diff erent ^groups, before they had diverged 

 much, should have accidentally resembled, to a certain. extent, 

 some one species. vYgu .wJU^ so see in t his lett er a stran ge 

 speculation, which I should not dare to" publish, about th e 

 appreciation of certain colours being developed in those species 

 which frec^uently behold other forms similarly ornamenfed! I 

 do notfeel at all sure that this view is as incredible as it may 

 at first appear. Similar id eas have passed through my mind 

 wlien considering the dull colours of all the organisms which 

 inhabit dull-coloured regions, such as Patagonia and the 

 Galapagos Is. I suppose you kno w Mr. Riley's exc ellent 

 essay on mimicry in the last report on the noxious insects of 

 MissouFi or some such title. 



"I hope your work may be in every way successful. 

 " I remain, dear Sir, yours faithfully, 



" Charles Darwin." 



The next letter deals with mimetic resemblance : — 



"Mar. 28, 1872. "Down. 



"Dear Sir— I thank you for your information on various 

 subjects. The point to which you allude seems to me very 

 obscure, and I hardly venture to express an opinion on it 

 Myfirst__impression is t hat the colour of an imitating for m 

 might be modified to any extent without any tendsucyJieipg 

 given to the retention of ancient structural Deculia jities. The 

 difficulty of the subject seems to me to follow fromjiur 

 complete ignorance of the causes which have led to the gene ric 

 differences between the imitating and imitated forms. The 

 sublet liowever**seems worth investigating. If the imitator 

 habitually lives in company with the imitated, it would be apt 

 to follow in. some respects the same habits of life, and this 



