COMMON BAT, PIPISTRELLE OR FLITTER-MOUSE 121 



precisely as in the case of other bats. On the other hand, Mr 



Whitaker suggests that pairing may take place during the 



latter half of May, at which time he has noticed bats 



chasing each other, a fact not necessarily evidence of pairing.^ 



Unfortunately, no precise observations exist for Britain. It 



is, however, certain that the date of birth varies a good deal, 



at least from late June^ to early August, but it is never, so 



far as is known, so early as to be inconsistent with Messrs 



Rollinat and Trouessart's results. Thus Mr H. Lyster 



Jameson,* when visiting Bohoe Church, Ireland, on nth 



July, found a number of young Pipistrelles, from a few 



days old to half- grown individuals, crawling about the 



floor of the church, having fallen through a hole in the 



ceiling. As regards July births, four captive females, in 



the possession of Mr Whitaker, produced their respective 



young on the 2nd, loth, i8th, and 19th; while Mr Coward 



found an embryo nearly ready for birth in a female killed on 



the 4th of the same month. The earliest of these would, no 



doubt, have been born in June, and the possibility of early 



births is further strengthened by the capture of a young one 



on the wing on 9th August at Exeter,* and of another at 



Kilmanock, County Wexford, Ireland, on the 13th. Allowing 



seven weeks each for gestation and rearing, the birth of these 



two bats must have taken place some time between 21st and 



25th June. Their southern habitats sufficiently account for 



the early date, and it is interesting to note that the Wexford 



bat was fully grown, although certainly immature. 



In two of Mr Whitaker's bats the known period of gestation 

 was not less than forty-one and forty-four days, and in a third it 

 probably reached forty-nine. The mother was captured between 

 27th and 31st May, had for companions two males of 

 her own species, and when she died on 14th July was found 

 to contain a small embryo, "probably not more than half- 



> See his " Notes on the Breeding Habits of Bats," Naturalist, 1905, 325-330. 



2 A statement by J. J. Briggs {Zoologist, 1848, 2278) that the bats in Melbourne 

 Church, Derbyshire, "bring out their young about June 17th," is unfortunately some- 

 what indefinite as regards the exact species. 



' Irish Naturalist, 1896, 95. 



* Now in the Exeter Museum, and kindly submitted to me for examination by 

 Edwin HoUis. 



M 



