44 



NORTH AMERICAN BATS. 



fur in both is of dark plumbeous, the tip alone being a hue at 

 variance with it. These tips in S. hesperus are brownish-gray 

 and fawn, in S. pijnstrellus being a rich olive-brown. In size 

 it corresponds to that small European group with incurved tragus 

 and rounded ear, of which S. alcythoe and S. ay-isfijype are mem- 

 bers. It difiFers from it, however, in the additional molar on the 

 upper jaw. S. hesperus, therefore, is a form uniting, so far as 

 can now be determined, the peculiarities of S. pipistrellus and 

 S. alcythoe and aristippe. 



Measprements. 



Li.ST OF Specimens. 



Fig. 40. 



S. hesperas. 



