My dear Mr. Darwin,

Herewith I return the No. of Kosmos which you were good enough to lend me— accept my best thanks for the loan of it.¹ I have transferred Fritz Müller’s paper in extenso to our ‘Proceedings’ having obtained (as you suggested) permission to do so from D^r. Ernst Krause who is also going to be so kind as to send me galvanoplasts of the wood-cuts.² Fritz M’s arguments for the production of mimicry between two butterflies both protected by distastefulness appear to me very ingenious & I beg to call your special attention to the concluding portions of his paper as you say it is new to you. You will see that his proof rests upon the belief that young birds & other insect persecutors do not come into the world with a knowledge of what species to eat & which to avoid, so that a certain number of distasteful individuals have to fall victims to this inexperience.

Unfortunately for the argument F. M. adduces no facts in support of this view. Can you recall any observations on this subject? Jenner Weir says that in his aviary a distasteful caterpillar was always recognized at once, but it appears to me that the case is hardly analogous, inasmuch as such caterpillars always hang out danger signals in the way of brightly coloured stripes, hairs or spines.³ To suppose that young birds can at once distinguish among the myriad insect forms by which they are surrounded the palatable from the unpalatable is to credit them with an instinctive knowledge of species that might be envied by our most ardent Iconographers. I will send you the translation of the paper & the discussion to which it gave rise as soon as it is in type.⁴

Yours sincerely, | R. Meldola.