doubt a great step will be gained as to exact nomenclature when the Index issues from the press.
It has long been known that certain beetles, notably the Longicorns, squeak loudly when excited, the sound being produced by the friction of a file-like area on some part of the body against an adjoining edge as the parts are moved rapidly over one another. Stridulating organs seem, however, to be far more common among beetles, and much more diversified in position, than has hitherto been thought to be the case. Mr. C.J. Gahan, giving an account of these organs in the 'Transactions' of the Entomological Society (Part III. 1900), has enumerated several genera and not a few families in which their presence had previously been barely suspected, if not altogether unknown. The Longicorns, it would appear, can no longer claim to contain the greatest relative number of stridulating species, for in this respect they are exceeded by the Megalopidæ, while the Endomychidæ, Clythridæ, and Hispidæ seem to run them very close. The Tenebrionidæ also, and the Curculionidæ, furnish a considerable number of stridulating genera; and Mr. Gahan has shown that in the latter family the stridulating organs are not restricted to the males, as stated by Landois, but are frequently found also in the females, in some genera in the same position as in the male, in others in a different position. Genera of other families also are mentioned, in which the stridulating organs differ in position or structure according to sex, or are found in one sex only, usually the male. Darwin believed that the stridulating organs of beetles, like those of Crickets and Grasshoppers, serve as a sexual call, and have been gradually perfected by a process of sexual selection. Mr. Gahan, while accepting this view so far as it relates to the majority of adult beetles, points out that it is quite inapplicable to the stridulating organs discovered by Schiodte in the larvæ of several forms, some of which are even more perfectly developed than in any of the adult insects. Amongst other interesting facts to which he calls attention, is the great resemblance in position and structure which the stridulating organs of genera belonging to totally distinct families may have to each other, while at the same time the position of these organs may be quite different in genera belonging to one and the same family.
We have received a 'Guide to the Zoological Collections exhibited in the Bird Gallery of the Indian Museum' (Calcutta), by Mr. F. Finn. This is a primer on Indian Ornithology rather than a list of names or an enumeration of species. With this guide any fairly intelligent visitor who would take the trouble to read and examine the birds would return with some knowledge of avian matters of a sound and useful character. It is published by the Trustees of the Indian Museum.
