464 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XL 



unobserved. While searching for their insect prey they may be seen 

 to dart in and out among the branches and to penetrate, in various 

 directions, the dense mat of foliage overhead. They often pass within 

 a few inches of one's face, and yet it is rare that a sound is heard from 

 their delicate wings."* 



The nest is commonly in a hollow tree and, according to Merriam, 

 the young are generally two in number and are born about the first 

 of July. They commence to fly when about three weeks old (/. c., 

 p. 190). 



Specimens examined from Illinois and Wisconsin: 

 Illinois Glen Ellyn, Du Page Co., i; Chicago, 7; Palos Park, Cook 



Co., 1 = 9. 

 Wisconsin (M. P. M.) Milwaukee, 9; Delavan, Walworth Co., i; 



Burnett Co., i; Osceola, Polk Co., 4=15. 



Map illustrating approximate range of the Silver-haired Bat (Lasionycteris noctivagans) in 

 eastern North America. 



* Mamm. Adirondack Reg., 1886, p. 188. 



