Saal 
an 
SCIURUS., 
B. Size large, total length over 450 mm, 
a. Premolars —— 
a.’ Belly buffy or yellowish. 
a.’ Back gray. 
a./’’ Median area on back black; belly 
MABEL CBO OUT Gin iy es vias oooh Oh S. oculatus 
b.”’’ Median area on back washed with 
blackish; bellv buffy whitish............ S. toluce 
b.” Back yellowish gray. 
a./’” Belly rusty yellow; total length over 
PG MONG UA a isos Rain kde a)W wk Ridin Sok CN S. apache 
b.””” Belly more dingy yellow; total 
ISHS UMCER SOOM iy dcr sdk ie S, 7. lexensis 
b.’ Belly white. 
a.’” Back golden buffy or yellowish, overlaid 
with grizzling of black and white .....S. nayaritensis 
Back gray. 
a.” Back uniform gray or grayish brown; 
ears gray; total length under soo mm...... S. allent 
Back gray washed with yellowish on 
nape and back of shoulders; ears 
b 4} 
b ‘tr 
rusty. 
a * Tot: : ae at of 
a.” Total length under soo mm.......S. arizonensis 
b.* Total length over 500 mm........: S. a. huachuca 
b. Premolars * 
a.’ Nape patch strongly marked, rump patch 
present or absent, 
a.” Belly gray, rump patch well marked: 
ACCA TIe SUE Ts cuyiris yyoies-kada edie cot ey S. a, Jrumentor 
b.” Belly white or buffy. 
a.” Rump patch poorly defined or absent. 
a." Back dull whitish; belly white or buffy. S. socialis 
b.“ Back pale gray; belly white or buffy .......... 
ERR PEN Ee ices re a S. p. hernandezi 
b.””” Rump patch well defined. 
a." Middle of back gray; feet gray or 
blackish; belly white...........: S. p. colimensis 
b." Middle of back whitish; feet whitish: 
eye UMC! OP DULL 6s vey no oa xp) 46 nw we S. s. cocos 
c.”’ Belly rufous. 
a.’ Feet gray or blackish. 
a." Ribs, and sometimes shoulders, rufous. 
a.”"Back pale gray; top of head iron 
RM LM hin gh 515s, nck goad xv a aoe aD S. aureigaster 
95 
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10g 
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[23 
118 
ITS 
