336 bulletin: museum of comparative zoology. 



the ancestral stock was enabled to reach America from northeastern 

 Asia by follow ing land connections. In the particular accounts of the 

 forms recognized in this paper, I have indicated more precisely the 

 limits of distribution of each. 



Habits. 



The Big-eared Bats are essentially cave-dwellers. In the West 

 they frequently haunt the abandoned shafts and tunnels made by 

 miners. Numbers of them may inhabit a single such tunnel, but they 

 appear to rest singly, scattered along the rock walls, rather than in 

 clusters. J. K. Townsend (1839) in the journal of his expedition to 

 the Columbia River, Oregon, in 1834, relates that they often lived in 

 the storehouses at the forts, and were considered by the fur traders to 

 be beneficial in ridding such places of Dermestes. 

 ■ There is no evidence to indicate that any of the forms are migratory. 

 In the northern part of their range they retire to suitable ca\'erns to 

 hibernate. Hahn (1909) records finding specimens in caves at 

 Mitchell, Indiana, during the winter of 1906-7 and Butler (1895) 

 obtained two from Greencastle, Ind., 23 December, 1894. Brimley 

 (1905) reports one taken 1 February, 1893, in Bertie Co., North 

 Carolina. The University of Colorado has two from Boulder Coimty 

 in that State, captured in mid-winter, one on 21 January, 1912, in a 

 mine-tunnel where the temperature was 48° F., the other on 23 Febru- 

 ary, 1910, in a tunnel at fifty feet from the surface (altitude 7760 feet). 



The young are probably born in early July or even earlier in the 

 southern part of the range. Stephens (1906, p. 265) records a female 

 of C. m. imUesccns captured at San Diego, California, on 25 April, 

 that contained a single foetus. In the San Jacinto Mts., of Southern 

 California, Grinnell and Swarth (1913, p. 379) collected a female 

 containing a single large foetus about 5 June. They found that the 

 adult bats in a resting posture folded the long ears back against the 

 sides, close to the body, a habit which Hahn (1909) seems to ha\e been 

 the first to record in the case of specimens from Indiana. In a 

 freshly killed specimen, however, the ears project forward. 



History and Nomenclature. 



What is perhaps the first mention of a bat of this genus, is found in 

 Clapton's (1722, p. 594) account of the animals and other products of 



