Page:The Zoologist, 4th series, vol 3 (1899).djvu/504

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them use the interfemoral membrane as a pouch, nor have I been able to detect them using the thumb to rend asunder their prey, as Mr. O. Grabham (ante, p. 131) states they do. It is certain that the oblique downward plunge, so noticeable in the flight of the Noctule, is not always due to the loss of balance which would be involved in bringing the thumb to the mouth, for I have often seen Noctules plunge when the light was sufficiently good to show that both wings were fully extended. Mr. T.A. Coward, who has constantly watched Noctules in Dunham Park, suggests that a loss of balance would involve a vertical fall such as occurs when one wing is broken by shot, and not an oblique dive with extended wings. It must be remembered, however, that the diet of the Noctule is not restricted to large beetles (Melolontha and Geotrupes), and neither the pouch nor the thumb would be required to secure or dismember small insects; but whether this species uses the interfemoral membrane as a pouch, as its congener the Pipistrelle undoubtedly does, could be definitely settled by observing individuals in captivity.

A number of Lesser Horseshoe Bats (Rhinolophus hipposiderus), obtained at Cefn, Denbighshire, on March 4th, died before the end of the third day of their captivity. I could not induce them to feed, and they were so loath to take wing that I was unable to ascertain definitely the position of the tail during flight. In repose this organ is reflexed over the back (cf. B. Newstead, Zool. 1897, p. 538), and when on the ground the Bat carries it erect, i.e. at right angles to the long axis of its body. The legs showed very distinctly against a white ceiling when viewed from below, but this was possibly due to the shortness of the tail, and not to its being erect or recurved. Even if the tail were curved beneath the body during flight, its shortness and the small extent of the interfemoral membrane would constitute only an inefficient pouch, and it seems improbable that in the genus Rhinolophus these parts subserve the same purpose as in Plecotus, Myotis, and Pipistrellus.

I have put together these notes in the hope that others interested in the British Bats, who may be able to obtain the Barbastelle, Natterer's Bat, the Noctule, and more especially the Horseshoe Bats, will make observations on the methods adopted by them to secure their prey.