A MONOGRAPH OF THE BATS OF NORTH AMERICA. 157 



white tips, which become conspicuous on the ventral iis]»ect ofthe])re- 

 bracliiuiutofonn the so-called "shoulder tuft." At the pubis, the base 

 of the iuterfemoral membrane, and along the sides of the trunk, in- 

 chiding the axillae, the hair is silky and without the black base; it is 

 dull brown or cinerous, with a long, ocher tip. 



The memhrancs. — On the dorsum the hair extends from the body as 

 for as a line from the middle of the humerus to the ankle, and thus 

 extends slightly on the membrane beyond the tibia. A distinct patch 

 covers the back of the first metacarpal, the first interdigital space, and 

 the base of the second metacarpal bone; a mere fleck overlies the base 

 of the fifth metacarpal and the forearm near the elbow. On the venter 

 the membranes are covered with short, brown, obscurely bicolored fur 

 from the side of the body, and thence extends in a broad, oblique line 

 as far as the third digit; upcm the third interspace it stretches distally for 

 a distance equally one-half the length of the metacarpal bones. The 

 arm is covered, while the forearm is naked. The i^rebrachium is also 

 furred, save at the free border. The exterior of the auricle is covered 

 with dull yellow or ocher-colored hair, except at the broad, black mar- 

 gin, which, however, bears at the lower part a delicate fringe. The 

 interior of the auricle, both in front and back of the keel, is covered 

 with short hair. The tragus is a;lso slightly furry. The dorsum of the 

 iuterfemoral membrane is covered throughout with hair of the same 

 character as that of the loin, or with that in which the shaft assumes a 

 darker shade of butt" or brown; the ventral aspect of this membrane is 

 furred only at the basal third; the color can not be distinguished from 

 that of the pubis. 



Variations. — In No. 13281, U. S. N. M., Utah, the hair on the loin and 

 dorsum of the iuterfemoral membrane is of a cafe au la it brown instead 

 of the darker shades described in the text. 



In No. 4223, U. S. N. M., Petaluma, Cal., and No. 13207, also from 

 California, the shaft of the hair above the basal dark shade is almost 

 white, both on the dorsum head and body and the ventral aspect of the 

 neck. The colors about the face are deep brown instead of black. 



In No. 6184, U. S. N. M., British America, the ash tips on the venter 

 are absent except on the mammary lines. 



Some of the specimens are more gray on the sides of the neck than 

 others. 



The terminal point of the caudal series varies in length from 1"'"' to 

 5""". The prebrachium is small, joining as a rule the i»roximal half of 

 the forearm. The females as a rule have it somewhat larger than in 

 the males. 



The posterior border of the tragus at a point just above the notch is 

 thicker than the rest of the border in No. 5284, U. S. N. M. 



Membranes. — The prebrachium without details. The lines of the en- 

 dopatagium are indistinct, owing to the hairiness of the membranes. 

 The coraco brachial is fascicle extends to the free margin as in Minioj)- 

 teris and Eniballonura, 



