232 Bulletin American Museum of Natural History. [Vol. XX, 



mm., averaging about 61. It is thus much larger than A. 

 parvipes of Cuba, the forearm in which (in eight adults) 

 ranges from 55-57 mm., averaging 5 mm. less than in A. 

 jamaicensis. The skull, however, in A. insularis is much 

 larger than in A. jamaicensis, the width across m 2 -m 2 being 

 i mm. (about one tenth) greater, and the rostrum at the 

 base of the canines is also a millimeter wider, or about one 

 eighth wider. This indicates a much larger and more massive 

 skull than in A. jamaicensis, while the external measurements 

 are about the same. The mandibular rami are straighter or 

 less bowed and relatively slenderer. On the other hand, the 

 skull is very much smaller than in A. palmarum, as are also 

 the external measurements. It needs no comparison with 

 A. coryi, which is a small species, about the size of A. parvipes. 



Artibeus yucatanicus, sp. nov. 



Type, !ff, $ ad., Chichenitza, Yucatan, March' 17, 1896; Frank M. 



Chapman. 



Differs from A. intermedius from southern Mexico and Central 

 America in smaller size and absence of head stripes, in both these 

 respects resembling the West Indian forms of the genus, especially 

 A. parvipes of Cuba, from which it is not readily distinguishable. 

 Forearm, 55mm.; third metacarpal, 57; tibia, 24; foot, 14. Three 

 skulls average: Total length, 27 (type, 27.5); zygomatic breadth, 17 

 (type, 17.5); mastoid breadth, 14.4 (type, 15); interorbital constric- 

 tion, 7.2 (type, 7). Four skulls of A. parvipes measure the same in 

 total length, but a little less in zygomatic breadth. 



As previously stated (this Bulletin, IX, 1897, p. 4), the 

 Yucatan form closely resembles the Cuban form, much 

 more than it does specimens from southern Mexico (Isthmus 

 of Tehuantepec and Jalisco), these latter being referable to 

 A. intermedius of Costa Rica, though not typical. 



Specimens from the lower Orinoco, Merida (Venezuela), 

 and Santa Marta (Colombia) are not satisfactorily separable 

 from A. palmarum of Trinidad, although Merida examples 

 have a rather broader and more massive skull. Specimens 

 from western Colombia are darker, but in size and cranial 

 characters are not satisfactorily separable from A. palmarum. 

 A rather different type, however, occurs at Yungas, Bolivia, 



