VESPERTILIO. LASIURUS, 591 
inner one in vertical extent; the single upper premolar close to the 
canine; lower incisors in the direction of the jaws; first lower premolar 
half the size of the second, which exceeds the molars in vertical 
extent. (Dobson.) 
Color. Above dark brown, the extreme tips of fur hoary, as in 
V. noctivagans; paler beneath; the chin and throat as far back as a 
line connecting the posterior margin of the ears, pure white. 
Measurements. Total length, 86.36; tail, 38.10; head, 17.78; ear, 
16; forearm, 41.91; thumb, 8.89; third finger, 69.85; fifth finger, 50.80: 
tibia, 15.24; foot, 8.89. (Dobson.) 
The bats of the genus Lasiurus are chiefly recognizable by their 
rather heavily furred interfemoral membrane. They are of moderate 
size and the genus consists in North America of two species, one of 
which is split up into several races. 
11%. .Lasiurus. 
C= ee 
Ras 
33) I—1? 2—2? ~ 
Lasiurus Gray, Zodl. Misc., 1831, No. 1, p. 38. Type Vespertilio 
borealis Muller. 
Atalapha Peters, Monatsb. K. Preuss. Akad. Wiss. Berlin, 1870, 
p- 907. (nec Rafin.) 
Small premolar at base of upper incisor on inner side; incisor in 
contact with canine; ear broad, rounded at tip, hairy; back of inter- 
femoral membrane thickly furred; skull broad. 
KEY TO THE SPECIES AND SUBSPECIES. 
A. Upper part of interfemoral membrane hairy. 
a. Size small; forearm hairy, but without hairy 
tuft near elbow. 
a.’ Ears large. 
a.’’ Color variable, yellowish red to yel- PAGE 
oS Otay, Mad cute eee sr a Na aha saat L. borealis 592 
Dy awGeneralsaue deepeherry ted. . i425 .-. |. L.b. pfetffert 593 
b.’ Ears small. 
‘a.’ Back of interfemoral -membrane 
TNE TRA, as, Es oa L.b.tehotis 593 
b.’” Back of interfemoral membrane nearly 
IONE. Ese len eae Arse Se Meee a mA ee L. b. mexicanus 594 
