34 NELSON 



Back dark gray ; top of head iron gray or 



blackish hypopyrrhus p. 42. 



Ribs and shoulders not rufous 



Back dingy whitish ; nape patch rusty 



social is p. 62. 

 Back bluish gray in middle, remainder 



sooty brownish hirtus p. 56. 



Feet white 



Back whitish, rump and nape patches very 



bright cocos p. 65. 



'* Back gray 



Nape patch strongly marked, dark rufous 



effugius p. 54. 

 Nape patch not strongly marked, rusty 



yellowish poliopus p. 46. 



Nape and rump patches absent or not well defined 

 Nape and rump patches not well defined 



Back dark gray, sparingly or not at all mixed with yellowish hairs 

 Back and under side of tail dark iron gray ; feet gray 



cervicalis p 51. 

 Back and under side of tail paler gray ; feet white 



nemoralis p. 50. 

 Back pale gray mixed with yellowish hairs ; feet white 



Belly white hernandezi p. 48. 



Belly rufous , .poliopus p. 46. 



Nape and rump patches absent 



Back with broad median band of blackish ; rest of body whitish 



dorsalis p. 74« 

 Back without broad median band of blackish 



Belly pale gray ; back coarsely grizzled gray or yellowish gray 



yiicatanensis p. 70. 

 Belly not pale gray 

 Belly blackish or white 



Belly blackish ; back sooty blackish grizzled with yellow- 

 ish gray , nelsoni p. 55. 



Belly white 



Ear tufts present, whitish ; back gray or yellowish gray 



yucatanensis p. 70. 

 Ear tufts absent 



Ears bordered ivith black 



Back very dark, lateral line reddish ; ear patches 



rusty boothice p. 76. 



Back grayer, no lateral line ; ear patches very large, 



white .goldinani p. 82. 



Ears not bordered %vith black 



Back pale gray or yellowish, Jinely grizzled with 



black 

 Back gray 



Size large; total length about 570 mm.; back 

 vmiform ; no lateral line .griseus"^. 83. 



