The evolution of colour in Lepidoptera

At the Zoological Congress at Cambridge I imparted, especially for the exclusively English speaking and reading entomological public, some notions on this biological phenomenon, the existence of which I think to have discovered by studying the ontogenesis of caterpillars of Sphingidae, and also in the imagines of several families of Rhopalocera, more particularly in those of the Pieridae; the results of these studies have however been published in German. Now, before the Transactions of that Congress had been published, an article entitled » The Colours and Pigments of Butterflies” by Miss M. I. Newbegin appeared in the February number of »Natural Science”, in which, besides some other papers of these latter days on the same subject, she also discusses my study on the colour-evolution of Pieridae. Although I have tried at the afore-named Congress to disclose shortly the course of my observations and the results thereof as clearly as possible, from what Miss N. imparts I am afraid one must gather quite a false idea of what I have said. It seems to me she has not read my paper as carefully as might be desirable for anybody writing an article about it, and as a matter of course her judgment necessarily cannot be right. Since it is of the greatest importance for me to be well understood, so that other people may be led to submit my observations to a new investigation, to amplify them, if they come to see the exactness of the alleged facts and to ponder on my deductions, I think I may not yield to Miss N.’s opinion, but have to express my objections against it. All the more so as it is offering me an opportunity to point out how the different papers published since then on the same subject do not in any way conflict with or refute the justness of my view, as to the main point at least; and further to indicate the way which future investigations will have to follow, to get at results that can bring the necessary light into this matter. Miss N. is not well disposed towards my theory. No wonder, for she has a theory of her own about animal coloration, and mine does not agree with hers. One of the two must be wrong, partly at least, if not wholly so. This cannot be questioned, but 1 cannot for all that consider it as a matter of course that mine should be the wrong one, though indeed I am quite willing to admit that this may be the case. To decide this matter, however, a. closer examination than Miss N. has devoted to my investigations will be wanted. Nor do I believe this can be done by chemical studies alone; it seems to me, therefore, that Miss N.’s views resting almost exclusively on this basis, bear a too partial character. Certainly a chemical as well as a microscopical inquiry into the nature of colours is a very important thing with reference to the topic of my study, and I too made an ample use of the results obtained thereby, but doubtless it is erroneous to think this the only way in which this matter can be explained. There are people with black or fair or red hair, and surely chemistry and microscopy can reveal very important things as to the nature of these differences in colour, but they certainly never will explain the ethnological and anthropological phenomena of which these differences are the expression. Neither those sciences in themselves will ever be able to explain the biological facts to which the great difference in colour and wing-pattern among the Lepidoptera is to be attributed.