Gary Some Unrecorded Colorado Mammals. 25 



the Front and Medicine Bow ranges to Coulter (Middle Park), and Cana 

 dian Creek (North Park), where its range meets and slightly overlaps that 

 of consobrinus, of the western Colorado mountains. In color, operarius is not 

 unlike consobrinus, but it may be readily distinguished by its more robust 

 skull. Five skulls of adult male topotypes of operarius measure : Occipito- 

 nasal length, 32 ; basilar length, 24.6; zygomatic breadth, 18. Four skulls 

 of adult male consobrinus from Canadian Creek, North Park, measure : 

 Occipito-nasal length, 31 ; basilar length, 23.5 ; zygomatic breadth, 17.2. 



Specimens of operarius are in the Biological Survey collection from the 

 following localities : Gold Hill, Estes Park, Longs Peak, Boulder (5 miles 

 west), Nederland, Golden, Idaho Springs, Fort Garland, Antonito, Lake 

 City, Silverton, Mount Kelso, Elkhorn, Livermore, Berthouds Pass, Cana 

 dian Creek and Coulter.* Specimens taken in the vicinity of Colorado 

 Springs, and at Crested Butte, have been identified for E. R. Warren of Colo 

 rado Springs. 



Citellus tridecemlineatus parvus (Allen). 



This small spermophile is generally distributed over the desert areas of 

 western Routt and Rio Blanco counties. It was noted on Snake River, 

 30 miles northeast of Sunny Peak, August 22, 1906, and specimens were 

 secured at Escalante, August 31, and Rangely, September 13 and 17. It 

 was reported common in Lily Park, at the confluence of Snake and Bear 

 rivers ; in Browns Park, near the Utah line ; and on the Iron Springs 

 Divide, between Snake and Bear rivers. In 1905, two immature speci 

 mens were collected in the Axial Basin, Routt County, August 8, and an 

 adult male at Mud Springs, on the White River Plateau, 30 miles south 

 east of Meeker, August 18. The altitude of Mud Springs is 9,000 feet. 

 J. Alden Loring collected three of these spermophiles at Fort Garland in 

 July, 1892, while more recently, August 30 and 31, 1904, J. H. Gaut 

 secured two more at Antonito, Conejos County. 



Onychomys brevicaudus Merriam. 



This short-tailed grasshopper mouse is common on the sage plains of 

 North Park, and in the region between Snake and Bear rivers, in western 

 Routt County. It is represented by a series of eight July and August 

 specimens, taken at the following localities: Canadian Creek, east of Wai- 

 den, North Park ; Snake River, south of Sunny Peak, Routt County; Bear 

 River, south of Lay. 



A specimen collected by W. W. Granger at the forks of Snake River, 

 near Honnold, Routt County, September 1, 1895, is recorded by Allen, f 



Neotoma desertorum Merriam. 



This desert wood rat apparently enters Colorado from the Utah deserts 

 only in the extreme lower White River Valley. Four specimens were 

 collected five miles west of Rangely, September 15 and 16, 1906. It was 



* Both operarius and consobrinus have been collected at Coulter and Canadian Creek. 

 fBull. Am. Mus. Nat. Hist., VIII, p. 253, 1S96. 



