48 



NORTH AMERIOANi FAUNA 66 



length of skull 13.7, 13.1; interorbital breadth 3.4, 3.3; length of 

 maxillary toothrow 5.1, 5.0. 



Habitat and habits. — These bats probably hibernate in caves in the 

 wild forested regions of the Allegheny Mountains and migrate else- 

 where in the State during late winter and early spring. Most 

 specimens have been taken in caves located in hemlock forests. The 

 position of these bats as they hang on the walls or ceilings of the caves 

 is a definite means of identification. The arms, instead of hanging 

 parallel to the body, as generally found in M, ludfugus and other bats, 

 are extended about 30 degrees from the vertical. Little is known of the 

 feeding and breeding habits, but they are presumed to be similar to 

 M. ludfugus. 



Sfecimeris examined. — Montgomery County: Plummers Island, 2. 



Other records and reports. — Washington Comity: Kound Top 

 Mountain, near Hancock (bat banding record, U.S. Fish and Wildlife 

 Service) . 



SILVER-HAIRED BAT 

 Lasionycteris noctivagans (Le Conte) 



Vlespertilio']. noctivagans Le Conte, in McMurtrie, The animal king- 

 dom ... by the Baron Cuvier, vol. 1, App., p. 431, 1831. 



Type locality. — Eastern United States. 



General distribution. — Nearly all of North America, from the tree line in 

 northern Canada, south to Georgia, Texas, New Mexico, and California. 



Distribution in Maryland. — Probably breeds only in the Allegheny 

 Moimtain section, but occurs in all sections of the State as a migrant 

 in the spring and the fall. 



Distinguishing characteristics. — Teeth 2/3, 1/1, 2/3, 3/3, = 36; pelage 

 dark brownish-black, the ends of the hairs tipped with silver, giving 

 a somew^hat frosted effect, particularly along the middle of the back; 

 fur extends onto dorsal surface of interfemoral membrane; ears short 

 and rounded with broad, blunt tragus; skull flattened, and rostrum 

 broad. 



Measurements. — ^An adult male from Plummers Island, Montgomery 

 County has the following external measurements: Total length 116; 

 tail vertebrae 47 ; hind foot 10. Some cranial measurements of four 

 adults from Washington, D.C. are: Greatest length 15.8 (15.6-16.2) ; 

 zygomatic breadth (2 specimens) 9.9, 9.1; interorbital breadth 4.1 

 (4.0-4.3) ; length of maxillary toothrow 5.7 (5.6-5.8). 



Habitat and habits. — This bat is found most frequently flying about 

 ponds and streams in wooded areas. It roosts in hollow trees, in dense 

 foliage, and occasionally in buildings. It is sociable and often en- 

 countered in large groups. As in many species of bats, there is a marked 



