MICHIGAN 259 



momentum. The skin of the flanks is loose and dilat- 

 able, and when stretched by means of the limbs en- 

 ables the animal to drop slowly and gracefully, from 

 branch to branch, in a slanting direction. The distance 

 of these so-called flights is sometimes very great when 

 passing from tree to tree. I have seen them take leaps 

 which appeared to exceed a hundred feet in actual 

 length, passing from the top of one tall tree to the 

 centre of another that stood thirty feet from it. They 

 alight on the branch for which they are making with 

 unerring certainty and unsurpassable grace, undulating 

 the body and tail with elegant motion in mid-flight. In 

 passing from branch to branch in a perfectly horizontal, 

 or slightly ascending, direction, they cannot leap farther, 

 or better, than ordinary squirrels. 



They are omnivorous, devouring greedily all kinds of 

 coleopterous insects and larvae. They also devour birds' 

 eggs, which, probably, all squirrels do; but I suspect 

 them of destroying the young birds as well. I found some 

 unfledged young under trees inhabited by these squirrels, 

 which had the skulls bitten open and the brains sucked 

 out. The marks of the teeth showed that the depredator 

 was a very small animal ; and it seems certain that the 

 flying squirrel was that depredator, for different species 

 of small rodents never occupy the same tree, or in any 

 case only very temporarily. In this they resemble the 

 monkeys of South America ; and generally it seems that 

 mammals, and most birds, having selected a tree for 

 their special habitation, resent the intrusion of other 

 species ; and when they are not strong enough to drive 

 away the intruder, themselves forsake the tree and seek 

 another. 



The large black eye, which is surrounded by a narrow 

 white, or light-coloured ring, is a very beautiful feature 

 of these pretty little squirrels. 



Of other rodents I shall say nothing more than this, 

 that the common rats and mice of Europe, such as Mus 



