course, also coming from Mauritius. Speaking of Mauritius Letter 386 reminds me that I was so much pleased the day before yesterday by reading a review of a book on the geology of St. Helena, by an officer who knew nothing of my hurried observations, but confirms nearly all that I have said on the general structure of the island, and on its marvellous denudation. The geology of that island was like a novel. To A. Blytt.1 Down, March 28th, 1876. The following refers to Blytt's Essay on the Immigration of the Nor wegian Flora during Alternating Rainy and Dry Periods, Christiania, 1876. I thank you sincerely for your kindness in having sent me your work on the Immigration of the Norwegian Flora, which has interested me in the highest degree. Your view, supported as it is by various facts, appears to me the most important contribution towards understanding the present distribution of plants, which has appeared since Forbes' essay on the effects of the Glacial Period. To Aug. Forel. Down, June 19th, 1876. I hope you will allow me to suggest an observation, should any opportunity occur, on a point which has interested me for many years-viz., how do the coleoptera which inhabit the nests of ants colonise a new nest ? Mr. Wallace, in reference to the presence of such coleoptera in Madeira, suggests that their ova may be attached to the winged female ants, and that these are occasionally blown across the ocean to the island. It would be very interesting to 1 Axel Gudbrand Blytt (1843-98), the son of the well-known systematist M. N. Blytt. He was attached to the Christiania Herbarium in 1865, and in 1880 became Professor of Botany in the University. His best-known work is the essay referred to above, but he was also known for purely systematic work in Botany as well as for meteorological and geological contributions to science. The above facts are taken from C. Holtermann's obituary notice in the Berichte der Deutschen Bot. Gesell., Vol. XVII., 1899. 2 Auguste Forel, the distinguished author of Les Fourmis de la Suisse, Zürich, 1874, and of a long series of well-known papers. Letter 387 Letter 388 Letter 388 discover whether the ova are adhesive, and whether the female coleoptera are guided by instinct to attach them to the female ants'; or whether the larvæ pass through an early stage, as with Sitaris or Meloe, or cling to the bodies of the females. This note obviously requires no answer. I trust that you continue your most interesting investigations Letter 389 on ants. To A. R. Wallace. The following five letters refer to Mr. Wallace's Geographical Distribution of Animals, 1876. [Hopedene]', June 5th, 1876. expressing to you my though I have read only I must have the pleasure of unbounded admiration of your book, to page 184-my object having been to do as little as possible while resting. I feel sure that you have laid a broad and safe foundation for all future work on Distribution. How interesting it will be to see hereafter plants treated in strict relation to your views; and then all insects, pulmonate molluscs and fresh-water fishes, in greater detail than I suppose you have given to these lower animals. The point. which has interested me most, but I do not say the most valuable point, is your protest against sinking imaginary continents in a quite reckless manner, as was stated by Forbes, followed, alas, by Hooker, and caricatured by Wollaston and [Andrew] Murray! By the way, the main impression that the latter author has left on my mind is his utter want of all scientific judgment. I have lifted up my voice against the above view with no avail, but I have no Dr. Sharp is good enough to tell us that he is not aware of any such adaptation. Broadly speaking, the distribution of the nest-inhabiting beetles is due to co-migration with the ants, though in some cases the ants transport the beetles. Sitaris and Meloe are beetles which live "at the expense of bees of the genus Anthophora." The eggs are laid not in but near the bees' nest; in the early stage the larva is active and has the instinct to seize any hairy object near it, and in this way they are carried by the Anthophora to the nest. Dr. Sharp states that no such preliminary stage is known in the ant's-nest beetles. For an account of Sitaris and Meloe, see Sharp's Insects, II., p. 272. Published in Life and Letters, III., p. 230. 3 Mr. Hensleigh Wedgwood's house in Surrey. 4 doubt that you will succeed, owing to your new arguments Letter 3S9 and the coloured chart. Of a special value, as it seems to me, is the conclusion that we must determine the areas, chiefly by the nature of the mammals. When I worked many years ago on this subject, I doubted much whether the now-called Palearctic and Nearctic regions ought to be separated; and I determined if I made another region that it should be Madagascar. I have, therefore, been able to appreciate your evidence on these points. What progress Paleontology has made during the last twenty years! but if it advances at the same rate in the future, our views on the migration and birthplace of the various groups will, I fear, be greatly altered. I cannot feel quite easy about the Glacial period, and the extinction of large mammals, but I must hope that you are right. I think you will have to modify your belief about the difficulty of dispersal of land molluscs; I was interrupted when beginning to experimentise on the just hatched young adhering to the feet of groundroosting birds. I differ on one other point-viz. in the belief that there must have existed a Tertiary Antarctic continent, from which various forms radiated to the southern extremities of our present continents. But I could go on scribbling for You have written, as I believe, a grand and memorable work, which will last for years as the foundation for all future treatises on Geographical Distribution. ever. P.S.-You have paid me the highest conceivable compliment, by what you say of your work in relation to my chapters on distribution in the Origin, and I heartily thank you for it. From A. R. Wallace to C. Darwin. The Dell, Grays, Essex, June 7th, 1876. Many thanks for your very kind letter. So few people will read my book at all regularly, that a criticism from one who does so will be very welcome. If, as I suppose, it is only to p. 184 of Vol. I. that you have read, you cannot yet quite see my conclusions on the points you refer to (land molluscs and Antarctic continent). My own conclusion fluctuated during the progress of the book, and I have, I know, occasionally used expressions (the relics of earlier ideas) which are not quite consistent with what I say Letter 390 |