AMERICAN BATS OF THE GENERA MYOTIS AND PIZONYX 35 



General color grayish M. c. atacamensis (p. 192). 



General color not grayish. 



Size large, greatest length of skull usually more than 15 mm. 



M. c. alter (p. 194). 

 Size medium, greatest length of skull usually less than 15 mm. 



Color distinctly yellowish M. c. dinellii (p. 191). 



Color dark brown. 



Burnished tips of hairs on back rather conspicuous. 



M. c. oxyotus (p. 193). 

 Burnished tips of hairs on back obsolete. 



M. c. chiloensis (p. 190). 



Species Occubeing in Temperate North America 



Under side of wing furred to level of elbow ; skull with rostrum shortened and 



occiput unusually elevated (western North America) M. volans (p. 135). 



Size small, forearm about 35 mm., length of skull less than 13 mm. (Lower 



California) M. v. volans (p. 139). 



Size larger, forearm 37-40 mm. ; length of skull more than 13 mm. 

 Color buffy or ochraceous (interior of western United States). 



M. V. interior (p. 142). 

 Color dark brown. 



Upper parts dark reddish brown (northwest coast region). 



M. V. longicrus (p. 140). 



Upper parts ochraceous tawny (southern Mexico) M. v. amotus (p. 145). 



Under side of wing not furred to level of elbow ; skull with normal rostrum 

 and occiput. 

 Foot small, the ratio of its length to that of tibia usually ranging from about 

 40 to 46. 

 Hairs of back with long shiny tips; third metacarpal not so long as fore- 

 arm; skull larger, with flattened braincase and gradually rising pro- 

 file (United States) M. subulatus (p. 164). 



Belly warm buff, back ochraceous tawny (eastern United States). 



M. s. leibii (p. 171). 

 Belly whitish. 



Upper parts very pale, light buff to warm buff (Interior United States). 



M. s. subulatus (p. 168). 

 Upper parts less pale, bright golden above (southwestern United 



States) -M. s. melanorhinus (p. 169). 



Hairs of back dull-tipped ; third metacarpal usually as long as forearm ; 

 skull smaller, with rounded braincase and abruptly rising profile (Mex- 

 ico and western United States) M. calif ornicus (p. 148). 



Size larger, forearm usually 33.6 to 36 mm. (southern Mexico). 



M. c. mexicanus (p. 159). 

 Size smaller, forearm usually 30 to 34 m. 

 Fur of back distinctly tricolor, the hairs with a dark base succeeded by 

 a pale ring and a pale reddish tip (deserts of western United 



States) __— M. c. pallidus (p. 157). 



Fur of back not distinctly tricolor. 



Upper parts ochraceous tawny (western United States). 



M. c. calif ornicus (p. 151). 

 Upper parts nearly mahogany red (northwest coast region). 



M. c. caurinus (p. 155). 



