48 MAMMALS OF EASTERN MASSACHUSETTS 



Red bat; New York bat; Tree bat. Lasiurus bo- 

 realis (Muller), 



Not uncommon. Nocturnal, usually hanging up in trees 

 in daytime, and not so often found in caves and buildings. 

 Distinguished by bright rusty red color, always lighter on 

 lower surface. Hair somewhat tipped with white, and a 

 whitish patch in front of each shoulder. Base of wing and 

 whole interfemoral membranes, also base of ears thickly 

 covered with fur. Comes out earlier in the evening than 

 other bats, while it is still quite light, so that its bright 

 color can be readily seen. One of these was caught at 

 Topsfield this year, and it had four young clinging to it. 

 It often (as do other bats) takes its young with it when 

 seeking food. The little ones cling tightly around the 

 mother, and seem to interfere but little with her flying. 

 The bats usually seen about the electric lights in summer 

 belong to this species. 



Hoary bat. Lasiurus cinereus (Beauvois). 



Rare. Nocturnal, spending day in trees. Very large, 

 length 5.40 in. Expanse of wing 12 to 15 in. Much larger 

 than Red bat, but with same dense covering of fur over 

 the interfemoral membrane. Color mixed dark brown and 

 yellowish, the brown fur more or less tipped with silvery 

 white, grayish white below. This species is easily identi- 

 fied, even on the wing, by its very large size, sharp, nar- 

 row wings, and very swift flight. 



