342 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



A half-j-Town male (No. 20,536, U.S.N.M.), taken at Monument No. 

 66 (Lang's Ranch), in the Anima.s Valley, had acquired the winter coat- 

 ing to the posterior half of the body as early as July 5. This illus- 

 trates the importance of excluding young individuals when studying 

 seasonal changes of pelage in mammals of warm countries. 



Eem.arks. — Four specimens from Belen, on the Rio Grande, in 

 Texas, haye remarkablj' long tails, with considerable terminal black 

 on them. They are a good step from typical C. ludovicianus toward 

 C. msxicanus. 



Habits and local distribution. — Capt. John G. Bourke, U. S. A., 

 ' in an account of the Arizona Flora and Fauna," writing of the region 

 about Old Camp Grant, on, the San Pedro River, Arizona, says: 



And 80 with the animal life; the deer, of the strange variety called "the mule;" 

 the coyotes, badgers, polecats, rabbits, gophers, but not the prairiedog, which, for 

 some reason never understood by me, does not cross into Arizona, or, to be more 

 accurate, does just cross over the New Mexican boundary at Fort Bowie, in the 

 southeast [Cynomys ludovicianus arizonermi], and at Tom Ream's ranch, in the Moqui 

 country, in the extreme northeast [Ot/nomys gunnisoni']. 



In the year 1885 I observed immense colonies of Arizona prairie- 

 dogs in the region contiguous to the Southern Pacific Railroad in 

 southeastern Arizona, extending as far west as the town of Benson, 

 on the San Pedro River. Other colonies were located in the region 

 about the junction of the Gila and Sailt rivers, also in the Sulphur 

 Spring Valley. For miles the burrows of these animals are thickly 

 scattered over the plains south of the Pinaleno Range or Sierra Bonito, 

 where the soil is clayey and better suited to the habits of this animal 

 than the loose sand of most of Arizona. Here the "dogs" fairly rev- 

 eled and overran the country. As we rode amongst them their sharp 

 barking was incessant and their tameness surprising. We had no 

 difiiculty in obtaining as many specimens as we desired, as they were 

 easily killed with shotguns, although, from the form of their burrows, 

 many rolled out of reach before we could secure them. The burrows 

 descend at first obliquely for two or three feet, then make a sudden 

 bend in the opposite direction, so that, even when shot dead, their 

 rotund bodies will double up and roll down the incline past the angle 

 out of reach simply bj^ force of gravitj'^. We found that a shot deliv- 

 ered from exactly in front of the animal as it sat at the top of its 

 mound with head and shoulders above the rim of earth that formed 

 a breastwork around it, would almost always kill it instantly. A 

 good many occupied-burrows had no mounds whatever around them. 

 I saw three adults enter a single burrow, and Dr. Paul Clendennin, 

 U. S. A., who accompanied me, killed two at once that were barking 

 together in the same hole. White-necked ravens ( Corvus cryptoleucus) 



a On the Border with Crook, 2d ed., 1892, p. 9. 



