I20 VESPERTILIONID.E— PIPISTRELLUS 



Wilson and Mr A. H. Cocks in Mr Heatley Noble's cave at 

 Henley-on-Thames, nor does Monsieur Gadeau de Kerville' 

 include it amongst the seven species revealed by a three 

 hours' search in the " Grotte de la Briqueterie, Seine-Inferieure," 

 France. In fact, he states expressly that he has never met 

 with it in such situations. 



There is some evidence to show that, like the Noctule and 

 Leisler's Bat, the Pipistrelle regularly varies its hiding-place 

 with the season, the sleeping-places of summer being frequently 

 distinct from the hibernacula of winter. One such instance 

 has been placed on record by Mr F. Boyes,^ who knew of a 

 retreat at Bishop Burton, near Beverley, from which no fewer 

 than one hundred and twenty-six Pipistrelles had been counted 

 as they emerged in summer, yet it was deserted in winter. In 

 its winter retreats, at all events, the animal is often solitary, but 

 immense troops gather together in summer. In these, unlike 

 the Noctule and Leisler's Bat, both sexes participate, and a 

 Hampshire colony was estimated by Mr Whitaker to include 

 from three to four hundred individuals.' 



The voice of the Pipistrelle is feeble when compared with 

 that of the larger bats, and can only be appreciated by sharp 

 ears, but Ovid was clearly guilty of poetic imagination when 

 he wrote of it that " Minimam pro corpore vocem emittunt,"*' 

 In truth, the little creature shrieks with might and main when 

 irritated, and it is hardly its fault, its gamut not being intended 

 for human ears, that its efforts are to most of us barely per- 

 ceptible. Mr Oldham remarks that individual bats differ widely 

 in the matter and manner of their utterings. 



As with other bats, the breeding season is probably 

 autumnal, but hiemal activity is accompanied by desul- 

 tory pairing of the extent of which we are ignorant. Messrs 

 R. Rollinat and E. L. Trouessart,^ whose interesting researches 

 on the breeding habits of bats have been already dis- 

 cussed at length, are quite firm in their assertion that, no 

 matter how frequently such winter breeding may take place, 

 as they admit it does, fecundation is retarded until spring 



' Bull. Soc. Amis Set. Nat. (Rouen), 4th April 1901, reprint, 2. 

 ^ Field, 29th August 1903, 405. ^ Naturalist, 1907, 77. 



* Metamorphoses, lib. iv., 10. " Supra, p. 32. 



