Anniversary Address Author:John Obadiah Westwood Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: volume of Dr. August Weismann's ' Studien zur Descendenz Theorie,' Leipzig, 1876, large 8vo, with five coloured plates; the first division of the memoir being en... more »titled "Ontogenese und Morphologic der Sphingiden-Zeichnung," and the second division " Ueber den Phyletischen parallelismus bei metamorphischen arten." The first four plates illustrate the variations in the colours and marks of the larvse of the Sphingidee, and the fifth those of Saturnia Carpini, one or more segments of the body in different specimens and varieties being represented: 225 pages of small print are occupied in the discussion of this subject, to which, as appears to me, far too much importance has been attached. Every fact, however, bearing on this curious question deserves to be carefully investigated, even if it extend no further than the darker or lighter colour of certain broods of insects. In this country Lycsena Artaxerxes offers a curious instance of this subject. It is, moreover, well known that in certain localities, especially in the northern parts of England and Scotland, certain pale- coloured moths assume a darker coloration, and thus, as we learn from an article on "Melanism," by Mr. Edwin Birchall, F.L.S. (Entom. M. Mag., November, 1876, p. 131), near Leeds, Aplecta nebulosa and Xylophasia polyodon are often perfectly black, and the "black pepper" (Biston betularia, var.) is well known, although, as described by the late E. S. Edleston in ' Newman's Entomologist' (ii. p. 150) sixteen years previously, it was almost unknown near Manchester. The dark variety had, however, so much increased subsequently that he considered the original pale type of the species would soon be extinct in the locality. Mr. Birchall speculates (sensu Darwiniano) on the causes of the melanism, and gives a list of ...« less