AMERICAN BATS OF THE GENERA MYOTIS AND PIZONYX 89 



grisescens or with a large individual of M. lueifugus as in Plate 1 

 (p. 7), Figures Za and 3&. First and second upper premolars slightly 

 drawn in from the tooth row so that the second is partly hidden in 

 exterior view behind the front corner of the third premolar. 



HahitS' — Myotic velifer is a colonial species, typically a cave- 

 dweller, so that its local distribution and abundance may frequently 

 be conditioned in part by the presence of caves suitable for habita- 

 tion. Ward (1891, 1904) found great numbers in a state of semi- 

 hibernation in the tunnel-like caverns formed in lava, on the vol- 

 cano of Perote, in Jalapa, Vera Cruz, Mexico, during the month of 

 February. The animals are quick to take advantage of the artificial 

 shelter offered by old buildings and are therefore considered as 

 "house bats " in parts of Texas and Arizona. Bailey (1905) has de- 

 scribed how they came from a considerable distance to drink at an 

 artificial pool in the dry country at Carlsbad, Tex., flying appar- 

 ently from the limestone hills several miles away, " straight for the 

 water pool without a crook or turn." Mine tunnels are also used as 

 roosting places. 



Remarks. — In its structural details Myotis velifer suggests a large 

 Myotis lucifugus, with the cheek teeth broadened but not sensibly 

 altered in structure. The form of the skull is less flattened than in 

 the smaller animal, the rostrum is broader, the interorbital constric- 

 tion relatively narrower, and the brain case fuller and more globose, 

 with sharply defined sagittal crest (compare figs. 3a and 3&, pi. 1, 

 p. 7). Externally it resembles Myotis grisescens^ which was con- 

 fused with it by Miller in 1897, but it is readily distinguishable by 

 the normal insertion of the wing membrane on the foot, and by the 

 darkened bases of the hairs on the back. 



MYOTIS VELIFER VELIFER (J. A. Allen) 



Vespertilio albescens Tbue, Proc. U. S. Nat. Mus., vol. 7, p. 603, 1885 (part, not 

 of Geoffroy). 



Vespertilio velifer J. A. Allen, Bull. Amer. Mus. Nat. Hist., vol. 3, p. 177, De- 

 cember 10, 1890.— H. L. Waed, Amer. Nat., vol. 25, p. 744, August, 1891. 



Vespertilio albescens velifer H. Allen, Monogr. Bats North Amer., Bull. U. S. 

 Nat. Mus., No. 43 (1893), p. 92, March 14, 1894.— Trouessaet, Catal. 

 Mamm. viv. foss., p. 132, 1897. 



Myotis velifer Millek, North Amer. Fauna, No. 13, p. 56, October 16, 1897. — 

 Trouessart, Catal. Mamm. viv. foss., p. 1285, 1899. — Elliot, Synops. Mamm. 

 North Amer., Field Columb. Mus., publ. 45, zool. ser., vol. 2, p. 401, March, 

 1901; List Land and Sea Mamm. North Amer., Field Columb. Mus., publ. 

 57, zool. ser., vol. 2, p. 517, June, 1901. — Miller and Rehn, Proc. Boston Soc. 

 Nat. Hist., vol. 30, p. 255, December 27, 1901. — Elliot, Land and Sea Mamm. 

 Middle Amer., Field Columb. Mus., publ. 95, zool. ser., vol. 4, p. 573, 1904.— 

 Trouessart, Catal. Mamm. viv. foss., suppl., p. 92, 1904.— Ward, Trans. 

 Wisconsin Acad. Sci., vol. 14, p. 647, 1904. — Bailey, North Amer. Fauna, 



58518—28 7 



