1867.] SEXUAL SELECTION. 275 



Can butterflies be polygamous ! i. e. will one male impreg- 

 nate more than one female ? Forgive me troubling you, and 

 I dare say I shall have to ask forgiveness again. . . . 



C. Darwin to A. R. Wallace. 



Down, February 23 [1867]. 

 Dear Wallace, — I much regretted that I was unable to 

 call on you, but after Monday I was unable even to leave the 

 house. On Monday evening I called on Bates, and put a 

 difficulty before him, which he could not answer, and, as on 

 some former similar occasion, his first suggestion was, " You 

 had better ask Wallace." My difficulty is, why are caterpil- 

 lars sometimes so beautifully and artistically coloured ? See- 

 ing that many are coloured to escape danger, I can hardly 

 attribute their bright color in other cases to mere physical 

 conditions. Bates says the most gaudy caterpillar he ever 

 saw in Amazonia (of a sphinx) was conspicuous at the dis- 

 tance of yards, from its black and red colours, whilst feeding 

 on large green leaves. If any one objected to male butter- 

 flies having been made beautiful by sexual selection, and 

 asked why should they not have been made beautiful as well 

 as their caterpillars, what would you answer ? I could not 

 answer, but should maintain my ground. Will you think 

 over this, and some time, either by letter or when we meet, 

 tell me what you think ? Also I want to know whether your 

 female mimetic butterfly is more beautiful and brighter than 

 the male. When next in London I must get you to show me 

 your kingfishers. My health is a dreadful evil ; I failed in 

 half my engagements during this last visit to London. 

 Believe me, yours very sincerely, 



C. Darwin. 



