1915. ] 



GEIs^uS THOMOMYS. 



39 



p. Size smaller, hind foot averaging 30 or less. 



g'^. Color dark tawny, clouded with black in winter pelage. 



h\ Hind foot of ^ about 30 fulvns (p. 80). 



Ji^-. Hind foot of $ about 27. 



f . Color dark, bordering on umber . .intermedius (p. 84). 



i'. Color brighter with less black on back texensis (p. 85). 



g-. Color bright or pale tawny. 

 h^. Color verv' bright tawny. 



i^. Incisors not conspicuously protruding beyond nasals, 



desertonim (p. 83). 

 i^. Incisors conspicuously protruding beyond nasals. 



Belly pale tawny nelsoni (p. 92). 



f'. Belly white or yellow. 



/j^ Belly white , goldmani (p. 94). 



7j-. Belly yellow meamsi (p. 87). 



})?. Color pale tawny. 



f . Color brighter, more buffy tawny lachuguilla (p. 88). 



i-. Color duller, more gra^dsh tawny perditus (p. 95). 



e^. Color not tawny. 

 f-. Color buff or orange, varying from light buff to ricli orange-buff. 

 g'^. Color bright orange-buff or buffy yellow. 



h^. Size large, hind foot of type (c? ad.) 36 magdalense (p. 61). 



h^. Size smaller, hind foot not over 33. 

 iy. Zygomatic arches abruptly constricted posteriorly, 



operarius (p. 77). 

 Zygomatic arches not abruptly constricted posteriorly. 



Rostrum very broad latiiostris (p. 78). 



p. Rostrum less broad aureus (p. 74). 



g^. Color buff or grayish buff. 

 h}. Color grayish buff. 



iy. Size large, hind foot of $ about 33. canus (p. 73). 



Size smaller, hind foot of $ about 30 perpes (p. 72). 



h?. Color clear yellowish buff. 



i^. Size large, hind foot of J averaging 34 albatus (p. 70). 



i^. Size smaller, hind foot of J" about 30. 



Nasals conspicuously truncate posteriorly russeolus (p. 60). 



f. Nasals usually slightly emarginate posteriorly. 



SkuU nan'ow and slender perpallidus (p. 68). 



/j^. SkuU short and wide chrysonotus (p. 71). 



/2. Color not buff or orange. 



g'^. Color gray, varying from light to dark brownish gray. 

 A\ Color dark brownish gray; claws stout; ears larger. 

 i^. Audital bullae long but not full and rounded. 



Skull not heavily ridged in old $ , hind foot about 30, 



talpoides (p. 96). 

 f. Skull heavily ridged in old c? , hind foot about 31, 



rufescens (p. 98). 



i^. Audital buUse full and rounded. 



jK Color lighter, bullae larger bullatus (p. 102). 



f. Color darker, bullae smaller nebulosus (p. 103). 



h^. Color light brownish gray or pale gray; claws slender; ears smaller. 

 i^. Audita! bullae large and globose. 



j^. Color very pale gray agrestis (p. 105). 



f. Color not so pale gray clusius (p. 100). 



