WCP2888

[1]¹

Wadham College,

Oxford

Nov. 16, 1907.

Dear Mr Wallace,

I am much pleased to hear that you have been interested in reading my lecture on Mimicry. The lecture as published suffers much from the absence of illustrations, of which I was able to show a good supply at Leicester. I have no copies printed [2] separately, but I am sending you the number of "Nature" which contains the discourse, and I would suggest that if this is too bulky for transmission to Brazil, the lecture might be cut out and sent by itself.

I think I must admit that you have hit a blot in the form of my argument. I do not know of any direct evidence that the brilliantly-coloured Pierines of the geneia Pereute and Euterpe are distasteful, though several of the species have been [3]² stated (by Fritz Müller³ himself and by Godman⁴ and Salvin⁵) to be abundant in individuals — in at least one case more so than the supposed "model", which is spoken of as a rare butterfly. There is, however, evidence of a direct kind in the case of some Eastern Papilios and the Pierine genus Huphina (Frank Finn⁶ in Journ.[al of the] Asiat.[ic] Soc.[iety of] Bengal, 1895-7.) I think, too, that most naturalists who have watched members of the African Pierine genus Mylothris in nature agree with Mr Trimen⁷ that it is a group protected by inedibility. This genus, by the way, forms the centre of the assemblage of "white on yellow butterflies with a marginal row [4] of bead-like black spots" referred to in "Tropical Nature." Several of the African Papilios (like some of the Eastern Papilios and Eupleas) were found by Dr. Longstaff⁸ and myself to have an unpleasant odour. (Proc.[eedings of the] Ent.[omological] Soc.[iety of] Lond.[on], Feb. 7, 1906).

But no doubt my reasoning would have been more cogent if it had taken some such form as this: — Among the S.[outh] American Papilios and Pierines we find many cases of evident mimetic association which cannot be accounted for on Batesian principles. Such [5]⁹ are the cases of interchange, where each side has acted to the other as both mimic and model. Such again are the instances where two "mimics" have approached each other more closely than either of them has approached the common "model." These cases are explicable if we assume inedibility as a property not confined to one member of the group, but [6] shared by some of the "mimics"; they are not explicable on any other supposition hitherto advanced. We are then justified in making this assumption, at least provisionally, especially as evidence exists that both groups — Papilios and Pierines — include distasteful members.

As to the prevalence of conspicuous white marks in Island forms, I am quite inclined to agree with you, though it should not be forgotten that white [7]¹⁰ may be highly cryptic, as Thayer¹¹ has shown in the case of the white bellies of birds and mammals.

I would gladly have said more about your instances of general resemblance, and also about other points that arise in connection with the subject, but I had to keep the lecture within bounds, and so, I fear, tended to become rather curt and dogmatic. The demonstration of lantern slides took some time, in addition to the more formal parts of the discourse.

May I venture to say that [8] it gave me special pleasure to be called on to speak on this subject in what, if I am not mistaken, is your native town?

Very truly yours | F. A. Dixey [signature]¹²