198 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. X. 



paler than in E. hilarii; hairs of back, head, and sides of neck broadly 

 tipped with Mars brown effecting uniform coloration of the upper parts 

 and entirely concealing the deep blackish brown basal color; under parts 

 mostly pale wood brown or Isabella color with the dark brown basal 

 color slightly exposed in a prepared skin; hairs of the inguinal region 

 bordering the interfemoral membrane soiled creamy without dark bases. 



Ears slightly thinner than in other species of Eptesicus; tragus 

 relatively slender, somewhat attenuated, and less blunt at the tip than 

 in E. hilarii; terminal tail vertebrae excerted as in hilarii. 



Skull small and light, decidedly smaller throughout than in E. 

 hilarii; braincase much less elevated posteriorly, its depth in front only 

 slightly less than behind; facial portion of skull relatively long; teeth as 

 in E. hilarii, but smaller. 



Measurements: Type, measured by collector: Total length 88; 

 tail vertebrae 37; hind foot 10; forearm (from dry specimen) 35.7; pollex, 

 with claw 4.7; third metacarpal 33; fourth metacarpal 33; fifth meta- 

 carpal 31.9; tibia 14.3; calcaneum 13.6; tragus, from anterior base 4.5. 

 Skull of type: Greatest length 14.3 (15.5)5* basal length 13.9 (15) 

 interorbital constriction 3.3 (3.8); zygomatic breadth 9.4 (10.1) ; breadth 

 of braincase 6.6 (7.2); palate length, including spine 5.7 (6.5); breadth 

 between tips of canines 3.1 (3.6); depth of braincase (inion to basioc- 

 cipital) 5.2 (5.8); upper toothrow, including canine 5.1 (5.7); breadth of 

 third upper molar 1.8 (2); lower toothrow, including canine 5.6 (6.). 



Remarks: Bats from various parts of South America usually as- 

 signed to Eptesicus hilarii, and perhaps representing a number of 

 recognizable subspecies, vary somewhat in size, but so far as known all 

 have decidedly larger, heavier skulls and teeth than the one above 

 described. Although this species has the forearm only slightly shorter 

 than in some specimens referable to hilarii, its skull is so markedly differ- 

 ent that it does not seem probable that it will prove to be a geographic 

 form of hilarii but rather a wholly distinct species which may be found 

 at localities inhabited also by typical hilarii. Two specimens from 

 Lagoa Santa, Minas Geraes, Brazil, have been used to represent E. 

 hilarii. Another from Itacoatiara near Manaos on the Amazon evi- 

 dently belongs to the same form. E. dorianus, E. arge, E. andinus, 

 E. magellanicus , and E. montanus all appear to be forms equalling or 

 exceeding E. hilarii in size. 



* Measurement^ in parentheses are those of a specimen (No. 20742) of E. hilarit 

 from Lagoa Santa, Brazil. 



