E. Raymond Hall, A New Subspecies of Pocket Mouse from Kansas
“ From the more western Perognathus flavescens flavescens Merriam (from Seward, Hamilton and Morton counties, Kansas) , cockrumi differs in being darker in all parts of the pelage except on the underparts which are white in both subspecies; the parts of the hairs that are Ochraceous-Buff in cockrumi are Light Ochraceous-Buff in flavescens; the back of cockrumi is blackish instead of yellowish. From the more southern Perognathus flavescens copei Rhoads (topotypes examined but not at hand as I write) , cockrumi differs in duller more blackish (less bright and less reddish) upper parts. ”
