136 Proceedings of the Biological Society of Washington. 



fused with pale huffy fulvous; dappling of back very distinct, in some 

 cases amounting almost to spotting; dull fulvous of nose showing less 

 contrast with top of head (which in this pelage is redder); tail much 

 darker fulvous, almost ferruginous, with subapical black band broad and 

 distinct; feet washed with buffy. 



Young. — The young, when first assuming the adult pelage, are strongly 

 dappled from behind the shoulders to base of tail. The pelages of the 

 young may be known as first and second. 



First coaf. — Pelage long, silky, rather sparse, buffy-yellowish in color, 

 soon (before the hairs of the second coat appear) becoming indistinctly 

 dappled on the back. 



Second coat. — The new coat comes in first on the head, a little later on 

 hinder part of back (from middle of back to base of tail) leaving the neck 

 and shoulders covered with the long silky hairs of the first pelage. This 

 area (anterior half of back) is gradually covered by the second coat, 

 mainly by the forward-creeping of the line of new hairs from the middle 

 part of the back. The dappling is always pronounced and is strongest on 

 the hinder part of the back, very rarely reaching so far forward as the 

 shoulders. 



The second pelage, which is attained when the animal is little more 

 than half grown, resembles that of the adult. Its general tone may be 

 either gray or buffy-fulvous, usually the latter. Of two young collected 

 by Jewett at Mountain Home, Idaho, on the same day, May 25, 1911, one 

 (No. 171, 329) is gray; the other (No. 171,327) buffy-fulvous. But in our 

 large series of young from several localities the gray pelage is rare. 



Cranial characters. — Skull large, broad and massive, with prominent 

 zygomata, large bullae, and heavy teeth. Compared with mollis (from 

 type locality, Fairfield, Utah): Skull larger and more massive; rostrum 

 and nasals longer; zygomata more spreading throughout; jugal much 

 broader and more massive; maxillary roots of zygomata (viewed from in 

 front) larger, broader, and more massive; anterior frontal region includ- 

 ing orbital shelf of frontal, more elevated; upper (superior) face of pre- 

 maxillary larger and usually reaching farther posteriorly; bullae larger; 

 teeth heavier, the toothrow longer (S.5 mm.). Skulls of adults vary in 

 the degree of bowing of the zygomata. The shorter skulls have the arches 

 strongly outbowed; the longer ones have them much less prominent. 



Measurements. — Average of 8 from type locality: Total length, 256; tail 

 vertebrae, 62.5; hind foot, 35.5. 



Remarks. — Citellus idahoensis inhabits the sagebrush plains of west- 

 central Idaho north of Snake River. The Biological Survey has large 

 series of specimens, collected mainly by S. G. Jewett, from Payette, 

 Nampa, Kuna, Orchard, and Mountain Home. 



Citellus leurodon sp. nov. 



Type from Murphy, in hills of southwestern Idaho west of Snake River. 

 No. 169,031 male young-adult, U. S. Nat. Museum, Biol. Survey Collec- 

 tion. Collected May 30, 1910, by S. G. Jewett. Original No. 112. 



Characters. — Size rather large, about equaling idahoensis from the 



