THE MAMMALS OF NEW JERSEY. 93 



The "wings" consist of immensely elongated fingers, between 

 which is a delicate Indiarubber-like membrane, which extends 

 down along the sides of the body to the hind feet, and also out 

 to the tip of the tail. The toes on the hind feet are not elongated, 

 and they, as well as the short-clawed thumb of the hand, are 

 used in grasping limbs, or other support, when they come to rest, 

 or wish to hang themselves up. 



Bats fly about at dusk and just before dawn and, to some 

 extent, throughout the night, and feed on insects of various 

 sorts which they catch on the wing. They may often be seen 

 about electric arc-lights, where such vast hosts of insects are 

 assembled every night during the summer, and where they must 

 be able to make an ample meal. During the day they hang in 

 trees concealed among the leaves, or congregate in dark garrets, 

 under the eaves of buildings, or in caves, or similar places of 

 refuge. Their teeth are somewhat like those of the shrews — 

 small and sharp, and their eyes are quite small. They utter an 

 extremely shrill, grating squeak when caught and irritated. Bats 

 are strictly beneficial to man, and in spite of the numerous 

 stories and superstitions connected with them, they are abso- 

 lutely harmless, and should be welcomed about our houses, 

 rather than driven away. Their repellant appearance and un- 

 pleasant musky odor will, however, always make them unde- 

 sirable visitors to the majority of mankind, in spite of their 

 good qualities. 



All of our New Jersey bats belong to a single family, the 

 Vespertilio nidce. 



Family VESPERTILIONID^. 



Ordinary Bats. 

 Our Bats belong to five genera, distinguished as follows : 



a. Membrane between the hind legs (interfemoral membrane), completely 

 furred above, uniform with back. lasiurus 



aa. Interfemoral membrane naked or only slightly hairy near the base. 



b. Fur black with white lips. Lasionycteris 



