A MONOGRAPH OF THE BATS OF NORTH AMERICA. 113 



extends well upon the lobe. The tragus is straight or slightly concave 

 on the inner border and convex on the outer; the tip is blunt. The 

 external basal lobe is rounded, turned slightly forward; the notch 

 above it is narrow but shari)Iy defined. A conspicuous postrictal wart 

 is present. The lips are fleshy and furnished above with a sparse row 

 of coarse hair. Other than a few coarse hairs the face is naked. The 

 snout is blunt, with scarcely any eniargination between the palmate 

 nostrils. The mental plate small, triangular, and obscurely defined. 

 The postmeutal wart is commonly present. 



The hair above is dark brown, or tawny, nearly black at the basal 

 half with dark brown (olive) to lustrous isabella-brown tips. Below 

 the colors are lighter, the general color being gray, pallid, or yellow 

 brown. The tips of the hair on the surface last named varies greatly 

 in tint among specimens of the same geographical range or locality. 

 I have seen many fawn-colored individuals from the North Atlantic 

 coast. In the neighborhood of Philadelphia specimens occur with 

 fawn-colored tips, though the rule is for the color to be as above de- 

 scribed. In the Western forms the tips may be obscure light buff.* 



The hair extends on the membranes above from the proximal half 

 of the humerus along the the side of the body to the ])roximal half of 

 the femur. With the exception of a. small portion of tlie prebrachium 

 as it joins the neck the wing membranes are naked, as is also the space 

 between the caudal vertebra? and the thigh. Beneath, the hair, as is 

 the rule in Chiroptera, covers a large surface. A sparse growth reaches 

 from the body to a point midway to or quite to the elbow, and, by a 

 well-defined hem, from the middle of the humerus to the middle of the 

 femur. The upper fourth of the interfemoral membrane is slightly 

 furred. 



In 11217, adult, from Brazos, Tex., the membranes are of a brown 

 color, the basal parts of the hair on the dorsum are light brown, while 

 the tips are of scarcely any different shade. In the venter the hair is 

 likewise light brown at basal half, but the remaining portion of the 

 hair is much paler. The ears and dentition are the same as in other of 

 the species. 



In 5335, adult, from Carson V'alley, Nevada, the colors are much the 

 same as in the example last named, except that the membranes are 

 much darker. 



In 12098, adult, from Santa Barbara, Cal., the external basal lobe, 

 without incuived upper border hem, extends upwards nearly as far as 

 the tip and completely concealing the external emargination; three 

 conspicuous transverse lines on the inside of the auricle. The colora- 

 tion is not distinct, being quite the same as in the average example. 



* "A fusciis presents a wide range of apparently individual variation in eolor. 

 Specimens from a single locality taken at the same season vary fron a light-yellowish 

 or golden tint to a deep 8e])ia brown." (J. A. Alh'n, Bull. Am. Mus. Nat. Hist., Ill, 

 1G9, 1<S90.) 



441— No. 43 8 



