114 SCIURUS. 



KEY TO THE SPECIES AND SUBSPECIES OF THE SUBGENUS. 



A. Size large. Premolars, ^. 



a. Above iron gray. PAGE 

 a.' Nape yellowish brown or rusty rufous. . .5. aureigaster 115 

 b/ Nape grizzled rufous or brownish. . . .5. a. hypopyrrhus 116 



c.' Nape yellowish or rufous brown 5. a. frumentor 117 



d/ Nape grizzled yellowish brown to chestnut 



brown S. p. nemoralis 1 18 



e/ Nape yellowish brown to rusty tinged 



with black S. p. colimensis 1 19 



f/ Nape rusty rufous, sometimes mixed 



with black and white 5. p. effugius 120 



g/ Nape fulvous or rusty brown, grizzled 



with black 5. p. cervicalis 119 



b. Above gray mixed with brown or yellow 5. polio pus 117 



c. Above pale gray and yellowish 5. p. hernandezi 118 



d. Above blackish, grizzled with yellowish brown . . .S. nelsoni 120 



e. Above bluish gray, grizzled S. n. hirtus 121 



f. Above yellowish gray tinged with black. 



a/ Ears yellowish brown 5. collioei 121 



b.' Ears rusty rufous S. c. nuchalis 122 



g. Above pale reddish, yellow, and black 5. sinaloensis 122 



h. Above grizzled dark yellowish 5. truii 123 



i. Above mixed white and black, tinged with 



yellowish or rufous S. socialis 123 



j. Above grayish or creamy white 5. s. cocos 124 



k. Above grizzled yellowish brown, washed 



with white 5. griseiflavis 1 24 



1. Above grizzled gray 5. g. chiapensis 125 



m. Above grizzled gray and black, tinged with 



yellowish brown 5. yucatanensis 125 



n. Above blackish gray, suffused with buff . . . 5. y. baliolus 126 



o. Above black 5. thomasi 1 26 



p. Above dark brown, mixed with grayish 5. adolphei 126 



q. Above dorsal band blackish or grayish 



yellowish brown 5. a. dorsalis 127 



r. Above dark chocolate 5. melania 128 



s. Above grizzled grayish brown. 



a/ Tinged with reddish 5. boothia 128 



b/ Washed with black S. b. belli 1 28 



t. Above grizzled yellowish gray S. variegatoides 129 



u. Above grizzled yellowish brown, dorsal re- 

 gion washed with black S. managuensis 129 



