40 THE ZOOLOGIST. 



doubt a great step will be gained as to exact noraeuclature 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 Megalopidce, while the 

 Endomychida, Clythrida, and Eiispidm seem to run them very close. The 

 TenebrionidcR also, and the CurculionidcB, 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 posi- 

 tion as in the male, in others in a different position. Genera of other 

 families also are mentioned, in which the stridulating organs differ in posi- 

 tion 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 larvae 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 

 m 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. 



