324 University of California Publications in Zoology  [Vou.17 
Diagnosis —Size medium (forearm 34 to 41.8 millimeters long) ; 
whole dorsal surface of interfemoral membrane furred; color ranging 
from rufous red or fawn to yellowish gray, some of the hairs tipped 
with whitish. 
Description: Head.—Muzzle short and broad; nostrils directed 
outward and downward, apertures in an alcoholic specimen 2 milli- 
meters apart. Eye small and inconspicuous. A glandular swelling 
on each side of head between nostril and eye. In an alcoholic speci- 
men the ears when laid forward reach barely to the mouth. Anterior 
border of ear strongly but irregularly convex from free point of 
anterior basal lobe to tip; through this portion of its periphery it 
forms almost a semicircle. Posterior border of ear concave from tip 
to one-third distance to posterior basal lobe, and convex on remaining 
two-thirds. Tragus slightly more than half height of ear, and tri- 
angular in general outline with tip directed forwards. 
Limbs and Membranes——Wing attached at base of toes. Foot 
less than half leneth of tibia; claws stronely curved. Calear slender, 
about twice as long as foot and considerably shorter than free border 
of interfemoral membrane; not lobed at tip in the specimens at 
hand. Tail unusually long (5 to 15 millimeters longer than forearm) 
and enclosed to extreme tip in interfemoral membrane (pl. 18, fig. 14). 
Pelage.—¥ ur everywhere full and soft; longest on dorsal surface 
between shoulders, where the maximum length is about 10 millimeters. 
Ear furred only on basal two-thirds of its dorsal surface; ventral 
surface of ear scantily haired along borders; otherwise naked. Fur 
on dorsal surface of wing continuous with that on body to a line 
running from ankle jomt to about middle of humerus; otherwise 
naked save for three small patches of hair, the first lying at base 
of thumb, the second extending along both sides of basal third of 
fifth metacarpal, and the third occupying anterior angle formed by 
junction of radius and humerus; ventral surface of wing membrane 
furred from just behind anterior border to a line extending from 
knee joint to basal third of third metacarpal. The fur constituting 
this strip is thicker and longer at the base of the fifth metacarpal 
than elsewhere. Whole dorsal surface of interfemoral membrane 
furred; but its ventral surface furred only at extreme base. Dorsal 
surface of toes furred. 
Color.—Hairs black at bases, except on face, chin, and membranes. 
In general, hairs on face and chin are yellowish, tipped with rufous. 
Hairs on back black for 1.5 millimeters from base; sueceeding 7 milli- 
meters pale yellowish; distal to this a rufous band about 1 millimeter 
wide, followed by an ashy tip of 0.5 millimeter. Ashy tips often 
lacking on posterior portion of back, as also on dorsal surface of inter- 
femoral membrane. On the latter area the black at bases of the hairs 
may also be wanting. 
IT am informed by Messrs. Miller and Hollister of the United States 
National Museum that in the eastern red bat the males are, on the 
average, brighter colored than the females, it being possible in most 
specimens to determine the sex by color alone. I find that this does 
not hold true with our western subspecies. McAtee (1907, p. 8) men- 
tions the resemblance of an individual of the eastern red bat to a 
withered leaf caught among the twigs of a tree. This suggests a 
protective value for the reddish brown color of our species. 
