﻿128 



NOKTH AMERICAN FAUNA. 



Teeth. — The teeth of BJuxjei'sa gracilis (fig. ^0) differ from those of 

 i?. tumida in numerous details. The crowns of the upper molars are 

 much narrower on the Jingual side and the posterior upper molar is 

 considerably broader. The front lower premolar is slightly larger than 

 in E. tumida^ but otherwise the mandibular teeth show no distinct 



differences. 



Measurements. — See table, 

 page 129. 



^pecim ens e x a m ined . — 

 Total number, 3, from the 

 following localities: 



Isthmus ofTeliuuiitej^ec, 1. 

 Puebla: Piaxtla, 2. 



General remarl's. — Bhoge- 

 essa gracilis is so readily 



Fig. 40.— Teeth of (a) Rhogeessa tumida and (&) E. gracilis (Jigtina'UlshedfrOm the Other 



species of the genus by its 

 slender form and very large ears that no detailed comparisons are 

 necessary. 



This is the only species of North American YespertUionidw in which 

 I have found any sexual differences in cutaneous structures. 



RHOGEESSA ALLENI Thomas. 



1892. Ixltogeessa alleni Thomas, Ann. & Mag. Nat. Hist., 6th ser., X, p. 477, Decem- 

 ber, 1892. 



Ty^w locality. — Santa Eosalia, near Autlan, Jalisco, Mexico. Type 

 in British Museum. 



Geograx^Mc distribution. — Bhogeessa alleni is known from the type 

 locality only. 



Characters. — As I have not seen the type and only known specimen 

 of this bat, I copy Mr. Thomas's original description: 



"Decidedly larger than Bh. parvula ; muzzle obliquely truncate as 

 in that species. Ears large, laid forward they reach about 1 or 2 millim. 

 beyond the nostrils; their inner margin very convex forwards below, 

 straight or even slightly concave above; tip narrowly rounded off; 

 outer margin concave below the tip, then straight, becoming slightly 

 convex below, outer basal lobe but little marked. Tragus long, its 

 broadest point opposite to base of its inner edge; inner edge straight 

 or slightly concave, tip rounded, outer. margin slightly convex, the edge 

 indistinctly crenulate, somewhat as in Antrozous paUidus ; a marked 

 lobule at the base of the outer margin, above and below which there is 

 a concavity. Thumb very short and thick, no longer than in Bh . parmila. 

 Posterior edges of wing-membrane bordered with white, bifid tip to 

 fourth finger unusually distinct; wings from the base of the fifth toe; 

 post-calcareal lobe small and narrow; tip of calcar projecting slightly 

 from the back of the membrane; tail included in membrane to the 

 extreme tip." 



