FEB., 1912. MAMMALS OF ILLINOIS AND WISCONSIN CORY. 453 



Front view, showing 

 upper incisors and ca- 

 nines much enlarged. 



GROUP 2. Upper incisors (front teeth between canines) 4. 

 SECTION 1. Upper surface of interfemoral membrane 



furred from y$ to ]4 its length, the rest bare. 

 Color sooty, frosted with white; whole number of 

 teeth 36. Genus LASIONYCTERIS, p. 462. 

 Color yellowish brown; whole number of teeth 34. 



Genus PIPISTRELLUS, p. 465. 



SECTION 2. Upper surface of interfemoral membrane entirely bare, or furred 



slightly at extreme base. 



Ears less than .75 inch long; fur of back, when rubbed, showing decidedly 

 darker at base; teeth in upper jaws 14; whole number of teeth 32. 



Genus EPTESICUS, p. 467. 



Ears less than .75 inch long; fur of back, when rubbed, not showing decidedly 

 darker at base; teeth in upper jaw 18; whole number of teeth 38. 



Genus MYOTIS, p. 455. 



Ears more than .75 inch long; teeth in upper jaw 16; whole number of teeth 

 36. Genus CORYNORHINUS, p. 476. 



Interfemoral membrane. 



KEY TO SPECIES 

 KNOWN TO OCCUR WITHIN OUR LIMITS. 



GROUP 1. Upper surface of interfemoral membrane (membrane connecting tail 



with legs) completely covered with fur. 

 Color of body hoary (brown mixed with grayish white); 

 length about 5 inches; upper front teeth (incisors) 

 between canines 2. HOARY BAT. 



Nycteris cinereus, p. 472. 



Color of body on upper parts reddish brown or yellowish 

 red brown; length about 4 to 4.25 inches; upper front 

 teeth (incisors) between canines 2. RED BAT. 



Nycteris borealis, p. 470. 



GROUP 2. Upper surface of interfemoral membrane (membrane connecting tail 



with legs) not completely covered with fur. 

 SECTION 1. Upper surface of interfemoral membrane 



furred from % to % its length, the rest bare. 

 Color of body sooty brown or blackish, frosted with 

 grayish white; length about 4 inches; whole 

 number of teeth 36. SILVERY BAT. 



Lasionycteris noctivagans, p. 462. 

 Color yellowish brown; length about 3.40 inches; 

 whole number of teeth 34. , GEORGIAN BAT. 

 Pipistrellus subflavus, p. 465. 



Interfemoral membrane. 



