MAMMALS 261 



mm. beyond the tip of the nose when laid forward: western States; 

 eastward to the eastern edge of the Rocky Mountains. 



2. Lasionycteris Peters. Medium sized bats with short, broad ears 

 and a broad tragus; dentition 2/3, i/i, 2/3, 3/3: i species. 



L. noctivagans (LeConte). Silver-haired bat (Fig. 150). Color 

 deep brown-black, the back with a silvery sheen; length 100 mm.; tail 

 41 mm.; forearm 42 mm.: North America, north of Mexico; common. 



Fig. 150. — Teeth of Lasionycteris noctivagans, the upper jaw at the left {from Miller). 



3. Pipistrellus Kaup. Small bats, similar to Myotis; dentition 

 2/3, i/i, 2/2, 3/3: 40 species, 2 in the United States. 



Key to the United States Species of Pipistrellus 



ai Tragus blunt, with tip bent forward P. hesperus. 



ao Tragus tapering and straight P. subflavus. 



P. hesperus (H. x\llen) (Fig. 151). Color light yellowish gray; 

 length 75 mm.; tail 32 mm.; forearm 30 mm.: southern and western 

 Texas to the Pacific. 



Fig. 151. — Teeth oi Pipistrellus hesperus (above) and P. subflavus (below), the upper jaw at 



the left (from Miller). 



P. subflavus (F. Cuvier) (Fig. 151). Color light yellowish brown; 

 length 85 mm.; tail 40 mm.; forearm 34 mm.: eastern United States; 

 westward to Iowa and Texas; Austral zone. 



Subspecies of P. subflavus 



P. s. subflavus (F. Cuv.). Eastern United States. 



P. s. obscurus Miller. Color duller and less yellow: eastern and 

 central New York (Lake George) . 



4. Eptesicus Rafinesque. Dentition 2/3, i/i, 1/2, 3/3; inter- 

 femoral portion of membrane naked: 5 species, i in the United 

 States. 



E.fuscus (Beauvois). Big brown bat; house-bat (Fig. 152). Color 

 sepia brown; length no mm.; tail 45 mm.; forearm 45 mm.: United 

 States and Mexico; common. 



