32 NORTH AMERIl'AN BATS. 



the tips only will be of a difiereiit color. The fur is soft and 

 long, ruiming up the back of the ears one-half their height in 

 many specimens, in others not more than a third that distance. 

 The basal part of the triangular interfenioral membrane behind 

 is hairy, the rest naked. Calcaneum -weak. 2s o extension of the 

 fur upon the wing membrane. Thumb and foot moderate. Back 

 of foot very slightly haired. 



These variations in the coloration of this species enable the 

 observer to arrange the specimens into three groups according to 

 the style of coloring of the fur. Thus the 1st group has chestnut- 

 brown tips on the back, with grayish-white tips on the belly ; 2d, 

 olive-Tarown tips on back, with fawn russet tips on the belly, inter- 

 mingled with whitish ; and 3d, deep chestnut-brown both above 

 and below, that of the front being but a shade lighter than that of 

 the back. In the specimen, JN'o. 5966, Williamstown, Mass., the 

 tips of the fur is everywhere v^diite at the tip. 



Both S. carolinensis and fuscus resemble S. serotinus of 

 Europe. The shape of the ear and tragus are very similar, and 

 the character of the face and tumidity of lii)S the same in all. 

 The latter species, however, is of a larger size than the others, 

 and the fur is almost entirely uuicolored — that is, there being 

 little or no difference between the coloration of the base and the 

 tip of each hair. 



Dentition, similar to that of preceding species. 



Major Leconte, in his " Observations on the Bats of North 

 America," claims the specific name fuscus, for what was formerly 

 known as the V. arcuatus, Say. In my attempt to include several 

 supposed distinct forms under one head, I have chosen the same 

 name. 



Palisot de Beauvois, as early as 1196, describes a species — 

 V. fuscus — in an old pamphlet catalogue, which, being but little 

 known, had received no attention prior to Major Leconte's 

 quotation. The description in this forgotten brochure does not 

 correspond very well with that of Scotophilas : for the number 

 of incisors in the upper jaw is less than the number actually 

 present. But this objection has not tin; importance that at first 

 sight it miglit appear to possess, inasmuch as the little incisor, 

 situated close to the canine, very frequently es('a])cs observation — 

 it being almost completely hidden in the growth of the adjacent 



