MAMMALS OF THE MEXICAN BOUNDARY. 



337 



season on the western part of the Colorado Desert. The same iw true 

 of the other mammals living- in those regions. 



HahiU and local diatr'AutiDii. — In 1885, when marching with the 

 Third Cavalry toward Texas from Fort Verde, Arizona, I first met 

 with the Yuma ground-squirrel — then only known from the specimens 

 collected by Maj. (afterwards Maj. Gen.) George H. Thomas, near 

 Halls Station on New River, just within the northern limit of Mari- 

 copa Count}'', Arizona. 1 saw them every day of our march until we 

 arrived at Mountam Springs, a day's march east of Tucson. From 

 this point eastward to Deming, New Mexico, I mistook Citellus spilo- 

 soma macrosjpilotus for this species, and embrace tWs occasion to 

 rectify my previous erroneous record of the existence of the Yuma 

 ground-squirrel in southeastern Arizona and at Deming, New Mexico. 

 On October 17, 1884, 1 saw some Yuma ground- 

 squirrels among the mesquites on the San 

 Carlos flats at the Indian Agency on the Gila 

 River. 



Near the Mexican Boundary this species is 

 abundant from the Santa Cruz Valley, Arizona, 

 to the Coast Range Mountains of California. 

 From January 25 to February 8, 1894, it onlj^ 

 appeared on the warmest days in places on both 

 sides of the Boundary where it is common. 

 Our first specimens were caught at Quitoba- 

 quita; they were not out of their burrows in the 

 region to the eastward, during the cold season 

 of our visit. It appeared to be scarce in Feb- 

 ruary on the plains immediately surrounding 

 the Gila Mountains, but was common at Adonde 

 Siding on the Gila River, and less so at Gila city, on the Gila, 15 

 miles above Yuma, Arizona. It was abundant along the Gila from 

 Gila city to Yuma, and down the Colorado River to the Gulf of Cali- 

 fornia. It was common, though generally not abundant, along the 

 Salton and New rivers to the Boundary Line and thence west as far 

 as Coyote Wells. It was most abundant at Indian Wells on the 

 New River. No other gi'ound-squirrel was found on the open desert; 

 but AmmospermopMlus leucurus (Merriam) appeared as soon as the 

 Coast Range was reached. Dr. W J McGee has written that ground- 

 squirrels are "common" in Seriland, western Sonora, Mexico, a 

 remark that may apply to this species." 



a SpermophUus sonoriensis Ward, described (Am. Nat., X.XV, Feb. 1891, p. 158) 

 from Hermosillo, State of Sonora, Mexico, is regarded by Merriam and Elliot as a 

 race of Citellus iereticaudus. 



Fig. 55.— Citellus tereti- 



CAUDUS. QDITOEAQUITA, 



Arizona. (Cat. No. 59888, 

 U.S.N. M.) 



30639— No. 56—07 M- 



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