io6 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XI. 



struck a few blows with a stick, they will come out and appear to be as 

 lively as usual. 



In an article in The Oregon Naturalist Mr. W. E. Snyder says, 

 "I recall having found (at Beaver Darn, Wisconsin), in the winter of 

 1890, what I consider almost a large family. One side of a large bun- 

 oak tree was dead while the other was yet alive. The tree was a hollow 

 one. Breaking in the dead shell, I found twenty-two full-grown 

 Flying Squirrels, Sciuropterus volans. Of course it was several families 

 unjted as one, for protection from the rigors of a Wisconsin winter" 

 (I. c., p. 9). 



Specimens examined from Illinois, Wisconsin and adjoining states: 

 Illinois Willow Springs, i ; Golconda, Pope Co., i ; Warsaw, Hancock 



Co., i; Olive Branch, Alexander Co., 1=4. 

 Minnesota Aitkin, Aitkin Co., 2. 

 Indiana La Porte, i ; Kankakee marshes, 1 = 2. 

 Iowa Knoxville, i. 



Wisconsin (M. P. M.) Maiden Rock, i; Rochester, Racine Co., i; 

 Fountain City, i; Pine Lake, i; Elm Grove, Waukesha Co., 2; 

 Burnett Co., i; Stanley, i; Milwaukee, 2; Milwaukee Co., 3; (O. C.) 

 Nashotah, Waukesha Co., 8; Delafield, i; Pewaukee, i; (O.) Wai- 

 worth Co., 2 = 25. 



Sciuropterus sabrinus (SHAW). 

 NORTHERN FLYING SQUIRREL. 



Sciurus sabrinus SHAW, Gen. Zool., I, 1801, p. 157. 



Pteromys Hudsonicus STRONG, Geol. Wis., Surv. 1873-79, I. 1883, p. 439 (Wisconsin). 



Sciuropterus sabrinus BANGS, Proc. Biol. Soc. Wash., X, 1896, p. 162. MILLER, 



Proc. Bost. Soc. Nat. Hist., XXVI, 1897, p. 34 (Nipigon, Ontario). ADAMS, 



Kept. State Board Geol. Surv. Mich., 1905 (1906), p. 129 (Michigan). JACKSON, 



Bull. Wis. Nat. Hist. Soc., VI, 1908, p. 19 (Wisconsin). 

 Pteromys sabrinus LAPHAM, Trans. Wis. State Agr. Soc., II, 1852 (1853), p. 339 



(Wisconsin). 

 Sciuropterus volucella hudsonius MERRIAM, Mamm. Adirondack Reg., 1886, p. 206. 



Type locality Severn River, Keewatin, Canada. 



Distribution Extreme northern border of eastern United States 



northward (see map). 

 Special characters Decidedly larger than S. volans, and white fur on 



under parts plumbeous gray at base, instead of all white as in that 



species. 

 Description In summer: Upper parts tawny brown, strongly tinged 



with drab; cheeks grayish; a narrow dark ring around the eye; 



flying membrane largely dark drab brown on upper surface; under 



