222 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 



canines well developed, not peculiar in form; anterior upper pre- 

 molar minute, occupying the inner angle between canine and large 

 premolar; other cheek teeth strictly normal; m 1 and m 2 without 

 hypocone, m 3 much reduced, its crown area less than one-third that 

 of m \ the protocone, paracone, parastyle, and first commissure well 

 developed, the mesostyle and second commissure obsolete, though not 

 absent; lower molars with all the cusps welk developed, m 3 with dis- 

 tinct entoconid. Skull short and broad, the brain case high and 

 rounded, the rostrum sloping away rapidly in front so that its 

 upper surface is nearly in line with that of brain case; nares and 

 palatal emargination wide and shallow, the width of the emargination 

 distinctly greater than its depth ; palate sloping upward anteriorly, 

 and floor of brain case rising posteriorly so that the two surfaces are 

 set at noticeably different angles; audital bullae well developed but 

 not large, their diameter about equal to width of space between; 

 basisphenoid pits narrow and elongate, but distinct ; zygomata slen- 

 der, not expanded at middle or elsewhere. Ear short, rounded. 

 Wing with fifth finger much shorter than third, the third metacarpal 

 usually exceeding fifth by at least length of thumb, though by dis- 

 tinctly less than length of thumb in L. borealis. Interfemoral mem- 

 brane very large, most of its upper surface furred. Mammae, 4. a 



Species examined.— Lasiurus borealis (Miiller) and the related 

 forms, also L. cinereus (Beauvois) and L. semota (H. Allen). 



Remarks.— This genus is well characterized by the short, deep 

 skull, the graduated metacarpals, and the furred interfemoral mem- 

 brane. The only genus that it is likely to be confused with is the 

 closely related Dasypterus, from which it is distinguished by the pres- 

 ence of the small upper premolar (pm 2 ). 



Genus DASYPTERUS Peters. 



1864. Lasiurus H. Allen, Monogr. Bats N. Amer., p. 25 (part). 



1871. Dasypterus Petebs, Monatsber, k. preuss. Akad. Wissensch, Berlin, 



1870, p. 912 (subgenus of Atalapha). 

 1878. Dasypterus Dobson, Catal. Chiropt. Brit. Mus., p. 274 (subgenus of 



Atalapha). 

 1894. Dasypterus H. Allen, Monogr. Bats N. Amer. (1893), p. 137, March 



14, 1894. (Genus.) 

 1897. Dasypterus Miller, North American Fauna, No. 13, p. 115, October 



16, 1897. 



Type-species. — Lasiurus intermedins H. Allen. 



Geographic distribution. — America, from the southern border of 

 the United States (including Florida and the Gulf coast) southward; 

 not yet recorded from the West Indies. 



o. For notes on the mamma? and the unusual number of young in the Lasiurine 

 bats, see Lyon, Proc. U. S. National Museum, XXVI, pp. 425^420, January 26, 

 1903, and Ward, Science, n. s., XXII, p. 20, July 7, 1905. 



