388 On the Leaser Hoheshoe Bat. 



These figures need no comment. It is a well-known fact 

 that in many bats females average a trifle larger than males, 

 but so small is the average difference in size between 

 tlie sexes of this species (0*3 mm. in minimus in favour of 

 the females, 0*6 mm. in Mpposiderus in favour of the same 

 sex) that it is scarcely detectable except on careful measuring 

 of a tolerably large series. 



As already emphasized in my paper two years ago, there 

 are certain border districts in which the two races meet and, 

 to a ceitain extent, merge into one another. As yet we know 

 exceedingly little about the exact limits of this transitional 

 zone, but the detailed lists of specimens examined and 

 measured, as given above, may, perhaps, throw a little light 

 on the question. It will be noted that of tlie five full-grown 

 specimens 1 have seen from S.AV. Switzerland (St. Maurice, 

 St. Cergues, and Geneva), one is indistinguishable from 

 mimmus, one decidedly a hipposiderus^ whereas three (all 

 from Geneva) are rather intermediate but nearest to wiVu'wws ; 

 of the five full-grown specimens from N. Switzerland (Baar, 

 Thurgau), one is indistinguishable from viinimus though 

 having the maximum size of this form, whereas four are 

 decidedly liipposiderus ; the series is much too small to allow 

 of any safe conclusions, but, so far as it goes, it shows 

 that in S.W. Switzerland both forms occur as well as 

 intermediate examples, in N. Switzerland hipjwsiderus, as 

 might be expected, is the dominant form (four of five 

 examples), whereas a small percentage (one of five) is refer- 

 able to minimus. Although, as already said, derived from a 

 very small series of specimens, this result will probably prove 

 to be approximately correct, and it is so far from being 

 unexj)ected ihat it is, on the contrary, entirely in accordance 

 with what I could predict without hesitation two years ago. 

 — To this I can now add one fact more : not only does 

 viinimus go a certain distance northward into the area of 

 Mpposiderus, becoming probably rarer the farther north, but 

 I know on excellent authority * that Mpposiderus goes a 



* Dr. Senna, Florence, writes (translation from letter, Dec. 19, 1905) : — 

 " You have pointed out that hipposiderus ranges (so far as our continent 

 is concerned) over Central Europe N. of the Balkans and the Alps, 

 minimus o\er the Mediterranean Subregiou. This seems to be perfectly 

 true, generally speaking ; I find, for instance, that nine specimens from 

 Cyprus are decidedly minimus, several examples from S. Italy (Calabria, 

 Sicily) are, without exception, minimus ; but in middle and northern 

 Italy we heyiyi to meet with hipposiderus, about 15 per cent, of the indi- 

 viduals belonging to this form, as against 85 per cent, of minimus ; still 



farther north, as you say, we find hipposiderus I hope I shall 



get so much spare time that I can work out the range of these forms in 

 Italy on the basis of the cuUectiuiiti preserved in all, or most, of the 

 Italian Museums.'' 



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