On Azarcis " Chaiive-souris onzi^mey 493 



LXVII. — OnAzara's " Chauve-souri's onzi^me^^ (Mjotis ruber, 

 Geoff.) and a new Species allied to it. Bj Oldfield 

 Thomas. 



When giving an account of Mr. W. Foster's Paraguayan 

 bats* I was not able definitely to determine Azara's "Chauve- 

 souris onzi^me " (Mt/otis ruber, Geoff.), but suggested that a 

 certain fawn-coloured species already known to me from 

 Argentina might prove to represent it. 



Sir. Foster has now sent to us three specimens of a M'/otis 

 which, on grounds both of locality and the exactitude of its 

 agreement with Azara's description, I have no hesitation in 

 identifying witii his species. 



This bat, which must bear the name of Myotis ruber f, 

 Geoff., is a fairly large animal (forearm 40 millim.), with 

 rather short velvety fur and medium-sized ears deeply exca- 

 vated on their outer margin. In colour it is uniform rufous- 

 brown above (" Mars brown "), the hairs scarcely or not 

 darker towards their roots, and rather paler below, the poste- 

 rior belly and anal region gradually becoming strong ochra- 

 ceous yellow, just as in the same part of its body M. albescens 

 becomes conspicuously white. 



The skull is large and heavy for the group, with particu- 

 larly stout powerful canines, which are conspicuously visible 

 in an upper view of the skull. 



From this bat the Argentine one formerly referred with 

 doubt to M. ruber is clearly distinct, and there being appa- 

 rently no other name available, it may be called 



Myotis Dinellii, sp. n. 



Size less than in J/, ruber, the difference being most marked 

 in the skull. 



Fur comparatively long (hairs on back about 7-7*5 millim. 

 in length), wavy as in most species^ not velvety. Hairs 

 extending but little on to interferaoral above, and not at all 

 below j no interfemoral fringe. General colour above uniform 

 dull rufous-cinnamon, the basal halves of the hairs slaty 

 black; under surface dull " isabella," mixed with theslaty bases 

 of the hairs. Membranes uniformly dark, without whiter 



* Ann. & Mag. Nat. Hist. (7) viii. p. 443 (1901). 



t U'Urbiguy's correct reference to this bat under the name of " Vesper- 

 iilio ruber " is misquoted by Lataste (Act. tSoc. Sci. Chili, i. p. 79, 1892) 

 and Trouestart (Mamm. p. 131, 18'J9j as V. rufus. 



