AMERICAN" BATS OF THE GENERA MYOTIS AND PIZONYX 67 



Type locality. — Old Fort Yuma, Imperial County, Calif., on right 

 bank of Colorado River, opposite the present town of Yuma, Ariz. 



Type specimen. — In his original description, H. Allen (1864) men- 

 tions by number, four specimens (5387, 6019-21, U.S.N.M.) in alco- 

 hol, all from Fort Yuma, Imperial County, Calif., collected by Maj. 

 Gen. George H. Thomas. Lyon and Osgood (p. 291) were unable to 

 trace these specimens 20 years ago, and we have fared no better. 



Distribution. — Interior desert country of the Great Basin, from 

 the eastern edge of the Sierra Nevada of California eastward into 

 western Texas, and south into Lower California and in Mexico to 

 the State of Durango. 



Northward range yet to be determined; but the pale desert race 

 evidently merges into the darker M. yuTnanensis sociabilis somewhere 

 in Utah and Nevada. Skins are lacking to determine the exact 

 status of the race inhabiting southern Lower California. The sup- 

 posed occurrence of Myotis yuiiianensis yunianensis in Colorado 

 (Gary, 1911) turns out to rest on a misidentification of M. lucifugus 

 phasma.., though it is not unlikely that the smaller animal will eventu- 

 ally be found in the western part of that State. 



Diagnosis. — Palest subspecies of Myotis yvmunnen^is ; butfy above, 

 nearly white beneath. 



Description. — Color above very pale buffy, nearly pinkish buff or 

 pale, dull, cream buff (RidgAvay, 1912), the hairs dark, near fuscous, 

 for the basal half. Below, pale cartridge buff, the basal half of the 

 hairs fuscous except in the posterior region where they are whitish 

 throughout. The membranes are pale brownish, translucent, usually 

 edged with white along the interfemoral border and at the tip of 

 the tail as well as on the edges above the ankles. Specimens in 

 immature pelage are less pallid, nearly cinnamon buff above. 



Measuretnents. — For measurements see tables, pages 73, 75. 



SpeciTnens exa/mined. — Total number 354, from the following 

 localities : 



ARIZONA: Ehrenberg, 13 ale. (U.S.N.M.) ; Fort Mohave. 1 skin (U.S.N.M.), 

 type of macropus; Fort Verde, .5 skins (A.M.N.H.) ; Gila Bend, 3 skins 

 (U.S.N.M.) ; Huachuca Mountains, Cochise County, 1 skull (F.M.) ; 

 Jacob's Pool, 1 skin (U.S.N.M.) ; Rice (San Carlos Indian Reservation), 

 2 skins, 2 ale. (U.S.N.M.), nearly typical; Safford, 1 ale. (U.S.N.M.); 

 Tucson, 1 skin (U.S.N.M.) ; Yuma, 9 ale. (U.S.N.M.). 



CALIFORNIA: Argus Mountains, Inyo County, 1 skin (F.M.) ; Carrell 

 Creek, Inyo County, 1 skin (U.C.) ; Fort Yuma, Imperial County, 4 

 skins, 2 ale. (U.S.N.M.) ; Lone Pine, Inyo County, 1 skin (M.C.Z.), 2 

 ale. (U.S.N.M.) ; Mount Whitney, Tulare County, 11,000 ft., 1 skin 

 (M.C.Z.),1 ale. (U.S.N.M.) ; Owens Lake, Inyo County, 4 ale. (U.S.N.M.) ; 

 Potholes, Imperial County, 1 skin (U.C), 1 ale, 2 skins (M.C.Z.). 



