RODENTIA : SCIURID^. / 



hours upon a stump or limb of a tree close to the trunk, 

 and, holding a cone or a nut in their fore paws, gnaw 

 it briskly till they get all the food it contains. Dis- 

 turbed while upon the ground, the Chickaree ascends 

 the nearest tree, and, making for the outer branches, 

 leaps from these to another tree, and, passing thus from 

 tree to tree, is soon out of sight. Sometimes, however, 

 when suddenly startled, it ascends a tree a short dis- 

 tance, and commences chattering with great fury, and 

 leaping about as if in defiance of its intruder. 



The Mountain Gray Squirrel, >S. Fremontii, Aud. & 

 Bach., of the Rocky Mountains, resembles the Red. 



Richardson's Squirrel, 5. Richardsonii, of Western 

 North America, resembles the Red Squirrel, but is 

 larger. 



The Oregon Red Squirrel, 5. Douglassii, Bach., also 

 resembles 5. hudsonizis, but is larger. 



The Genus Pteromys Flying Squirrels is charac- 

 terized by a densely furred membrane extending later- 

 ally from the sides between the fore and hind feet, by 

 means of which the animal is enabled to glide from one 

 tree to another, supported as by a parachute. There 

 are long, bony appendages to the feet, which support a 

 part of this lateral membrane. Four North American 

 species have been described. 



The Common Flying Squirrel, P. volucella, Desm., of 

 the United States east of the Missouri, is about five 

 inches long to the tail, which is a 

 little less in length than the head and 

 body ; the fur very soft and silky, the 

 color light yellowish-brown above, 

 and creamy white beneath. 



The Northern Flying Squirrel, P. 

 hudsonius, Fischer, of the Northern 

 States, is larger than P. volucella. 



