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. 



117. Lasiurus. 



ij;C.S;PS;M.g = 3 ,. 



Lasiurus Gray, Zool. Misc., 1831, No. i, p. 38. Type Vespertilio 



borealis M tiller. 

 Atalapha Peters, Monatsb. K. Preuss. Akad. Wiss. Berlin, 1870, 



p. 907. (nee 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 



lowish gray L. borealis 592 



b." General hue deep cherry red L. b. pfeifferi 593 



b.' Ears small. 



a." Back of interfemoral membrane 



hairy L. b. teliotis 593 



b." Back of interfemoral membrane nearly 



naked L. b. mexicanus 594 



