AMEEICAN BATS OF THE GENERA MYOTIS AND PIZONYX 203 



COSTA RICA: Bebedero, 2 ale. (B. M.). 



ECUADOR: Cachavi, 500 ft., 2 skins (B. M.) ; Mouth of Ciuaray River, 



2 skins (A. M. N. H.) ; no exact locality, 1 ale. (B. M.). 

 NICARAGUA: Escondido River, 1 ale. (U.S.N.M.) ; Prinzapolka River, 2 



ale. (U.S.N.M.) ; Rio San Juan, 1 ale. (U.S.N.M.). 

 PANAMA: Tabernilla, 2 ale. (U.S.N.M.). 

 PARAGUAY: Asuncion, 3 skins (F. M.) ; Paraguari, 2 skins (A. M. N. H.) ; 



Tacuaral, 24 skins, 16 ale. (U.S.N.M.), 7 skins (B. M.), 4 skins (M. C. Z.) ; 



no exact locality, 3 ale. (A. M. N. H.). 

 PERU: Pto. Indiana. R. Amazonas, 10 skins (A. M. N. H.). 

 VENEZUELA : Maracaibo, 1 ale., type of Vespertilio mtindus H. Allen 



(A. N, S. P.) ; Rio Aurare, 1 skin (F. M.) ; Valencia, 1 skin (B. M.). 



ReTiKirJcs. — This species is at once recognizable among the South 

 American members of the genus by its large foot, relatively short tail 

 and tibia, globular brain case, short rostrum, and relatively weak 

 teeth. 



Geoffroy's Vespertilio albescens^ based on Azara's " Chauve-souris 

 douzieme," is the first name given to this species. The animal is 

 evidently common in Paraguay, where the late William Foster 

 secured a large series of skins now distributed among various 

 museums. In these skins, as made up by Foster, the necks are so 

 stretched as to present a nearly bare area at the nape where the fur 

 is thin, and this bare spot was at first supposed to be a specific char- 

 acter as compared with the condition in other Myotis (see Thomas, 

 1902). Throughout the wide range of the species there is very little 

 variation in size or color; but, though the specimens from Paraguay 

 are rather paler than those from farther north, particularly the series 

 from eastern Ecuador, the latter can be matched by others quite as 

 dark from Goya, Argentina, so that at present there seems to be no 

 ground for subdividing the species. The specimens from Barbacoas, 

 Colombia, were referred by J. A, Allen to his Myotis punensis {=M. 

 chilo'ensis atacamensis) , which they superficially somewhat resemble. 



Of the various names considered as synonyms of Myotis albescens^ 

 Wied's F. leucogaster was obviously applied to this species, as indi- 

 cated by the excellent figure showing the characteristic chocolate- 

 brown, pale-tipped fur, as well as the proportions of the forearm 

 and legs. Temminck's Vespertilio cenobarhus, based on a specimen 

 from an unknown locality in South America, is undoubtedly the 

 same. Though the complete tooth formula could not be given, Tem- 

 minck's figure shows the slender head and the long narrow tragus 

 characteristic of Myotis, while the proportions of tail to total length 

 and the description of the color correspond closely with those of 

 M. albescens. The same author's description of Vespertilio arsinoe 

 from Surinam, seems to apply also to M. albesceiis. It has a total of 

 six molars and premolars in each jaw, the short thin pelage and pale- 

 tipped hairs with clear white belly, and a forearm of about 33 mm., 



