I04 The Irish Naturalist. May, 



Of late 3^ears it has become a moot point whether the Hairy- 

 armed Bat, Noctule, and Pipistrelle should continue to be 

 grouped in the same genus ( Vesperugo), or whether the first 

 and second should be grouped apart from the third in a 

 genus for which the name Pterygistes has been proposed. 

 This alteration appears to have been rather reluctantly 

 accepted by Mr. Oldfield Thomas,'' who expressed himself as 

 doubtful whether the differences were sufficient to warrant it ; 

 and Mr. Millais is evidently of opinion that Mr. Thomas's 

 doubts were justified. For my part, I cannot help thinking 

 that the very wide difference shown to exist between the 

 feeding habits of the Pipistrelle and those of the two other 

 species amounts to a strong argument for the genus Ptery- 

 gistes, and that there must be some important internal 

 differences, sufficient to justifj' generic separation, between 

 those bats which take a whole night to satisfy their feeding 

 requirements and those that cram themselves to bursting- 

 point, either once or twice in the twenty-four hours, during a 

 70-minutes' career of mad excitement among the twilight- 

 flying beetles and gnats. 



By the way, I must not be taken as suggesting that the 

 large crepuscular Bats *'bolt" their food. On the contrar}', 

 nothing is swallowed by these animals which has not first 

 been masticated with the most consummate thoroughness. 

 In proof of this, I may mention that the contents of the 

 stomachs of several Hairy-armed Bats shot during their 

 evening flight were examined with great care at Dr. Alcock's 

 request by Professor G. H. Carpenter, who, however, found 

 all the fragments so minute that the species of only one 

 insect — the yellow-haired fly, Scatophaga stercora7'ia — could be 

 identified with certainty ; while among the countless other 

 fragments, chiefly dipterous, a few were found referable to 

 an Acalypterate muscid, a midge^ probably a Mycetophilid, 

 and some caddis flies (/.A^., vol. viii-, pp. 35 and 172). The 

 teeth of the Noctule, doubtless, do their work with equal 

 effectiveness, and all lovers of Gilbert White will remember 

 that passage in his letter of September, 177 ij in which he 

 gives Pennant the description and measurements of the two . 



^ Zoologist, 1898, p. 100 



