FIELD BOOK OF MAMMALS 



dark- tipped hairs on back. Upperparts pale wood-brown; 

 underparts pale yellowish gray. Total length, 3.4 inches; 

 tail vertebras, 1.55 inches; hind foot, .32 inch; forearm, 1.4 

 inches. Found "Along border of Transition Zone and 

 Upper Austral Zone in central and eastern New York." 

 (Miller) 



Western Bat; Canyon Bat. — Pipistrellus hesperus hesperus 

 (H. Allen). 

 Smallest of North American Bats ; ear short (barely reaching 

 to nostril when laid forward), bluntly rounded; tragus blunt 

 and inclined forward at tip. Above and below light yellow- 

 ish gray or whitish gray; pelage slate-colored at base. 

 Total length, 2.9 inches; tail vertebrse, 1.2 inches; hind foot, 

 .22 inch; forearm, 1.2 inches. Found in "Lower Austral 

 Zone in the western United States from southern and 

 western Texas to the Pacific coast. Limits of range im- 

 perfectly known." (Miller) 



Merriam Bat. — Pipistrellus hesperus merriami (Dobson). 

 Resembling typical hesperus but darker in color and slightly 

 larger. Color above and below warm buff. Total length, 

 3 inches; tail vertebrae, 1.2 inches; hind foot, .22 inch; fore- 

 arm, 1. 1 5 inches. Found in the Upper Sonoran and 

 Transition Zones from the Mexican line northwest through 

 California, east of the humid coast belt and west of the 

 Sierra Nevada to Butte and Tehama counties. 



The species of Pipistrellus are very small, erratic flyers and 

 are often found in large numbers in favored localities. These 

 Bats seem to be commonest over the southern part of their 

 range and show a preference for cliffs and rocky hillsides. 

 They are variously recorded as appearing on the wing soon 

 after sunset, at late dusk, and even at 9 a.m. 



The number of young is one or two, more often the latter. 



The North American forms of Pipistrellus live in caves or 

 crevices in the rocks. 



Genus Eptesicus 



Dentition: Incisors, f; Canines, \; Premolars, I; Molars, § = 32. 



Brown Bat. — Eptesicus fuscus 



and related forms 



Names. — Brown Bat; Big Brown Bat; House Bat. 



General Description. — A large Bat, brown in color and 

 without any peculiar development of nose, ear, or wing 

 structure. Ear of medium size, narrowly rounded at tip, ear 



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