390 TROCEEDINGS OF THE ACADEMY OP [^fay, 



(No. 06,491): Greatest length, 19 (21);^ basal length, 17.6 

 (19); ba.silar length, 14 (15.4); iuterorbital constriction, 4(4.6); 

 zygomatic breadth, 11 (12.8); mastoid breadth, 9 (10); breadth 

 of braincase above roots of zygomata, 8.6 (9); mandible, 13 

 (14.8); maxillary toothrow (exclusive of incisors), 6.8 (8); man- 

 dibular toothrow (exclusive of incisors), 7.6 (8). 



Specimens Examined. — Five (four skins), all from the type 

 locality. 



Remarks. — Autrozons minor is a well-marked local species, com- 

 binmg the dark color of A. pacifieus and the small size of A. 

 pallidus with a peculiar form of the molar teeth. 

 Pipistrellus oinnamomeus sp. uov. 



Type.— Aduh female (skin and skull), No. 100,231, United 

 States National Museum (Biological Survey collection). Collected 

 at Montechristo, Tabasco, Mexico, May 4, 1900, by E. W. Nel- 

 son and E. A. Goldman. Original number, 14,136. 



Characters. — La i-gest known American Pipistrellus ; forearm, 37; 

 greatest length of skull, 15. Ear shorter than that of P. sub- 

 flaviis, but much nari-ower. Color uniform cinnamon thi'oughout, 

 the individual hairs of the back with practically no ti'ace of tri- 

 color markings. 



Ears. — The ear resembles that of Pipistrellus suhflavus in general 

 form, but it is shorter and very much narrower. Tragus straight, 

 much like that of P. suhflavus, but narrower. 



Fur, Membranes, etc. — The fur is shorter and less woolly than 

 that of P. suhflavus, and it lacks the abundant sprinkling of long 

 hairs characteristic of the latter. At middle of back the hairs 

 forming the body of the fur are about 5 mm. in length. Inter- 

 spersed with these are others 1-2 mm. longer, but quite unnotice- 

 able except on close examination. In distribution of fur, as well as 

 in other characters of external form, Pipistrellus cinnamomeus 

 appears to be identical with P. suhflavus. 



Color. — Fur everywhere cinnamon, slightly more yellow than 

 that of Ridgway, particularly on the under parts. The individual 

 hairs are dark slate color at base, but this does not appear at surface 

 unless fur is disarranged. In favorable lights the cinnamon of the 

 hairs on the back may be seen to become lighter as it approaches 



^Measurements in parentheses are those of an adult female Antrozous 

 pallidus from Silver City, New Mexico (No. 66,110). 



