Dear Sir

I thank you for your information on various subjects. The point to which you allude seems to me very obscure, & I hardly venture to express an opinion on it.¹ My first impression is that the colour of an imitating form might be modified to any extent without any tendency being given to the retention of ancient structural peculiarities. The difficulty of the subject seems to me to follow from our complete ignorance of the causes which have led to the generic differences between the imitating & imitated forms. The subject however seems worth investigating. If the imitator habitually lives in company with the imitated, it w^d be apt to follow in some respects the same habits of life, & this perhaps w^d lead to the retention or acquirement of some of the same structural characters.

I wish you all success in your essay & remain | dear Sir, | yours very faithfully | Ch. Darwin