Vol. X, pp. 1-24 February, 1896 



PROCEEDINGS 

 BIOLOGICAL SOCIETY OF WASHINGTON. . 



A REVIEW OF THE WEASELS OF EASTERN NORTH 



AMERICA. 



BY OUTRAM BANGS. 



The present paper treats of all the weasels of eastern North 

 America west to and including the Great Plains. There is ap- 

 parently no portion of this vast region not tenanted by at least 

 one member of this cosmopolitan group. Generally one species 

 occupies a very large area, in the central part of which no others 

 are found, so that when two species occur together it is usually 

 at points where the edges of their ranges overlap. It has been 

 my experience that weasels are nowhere very abundant— never 

 sufficient!}^ so to exhaust their food su[)ply. They are held in 

 check by some natural cause, which may be the parasite that 

 attacks the frontal sinuses of these animals as well as those of 

 their relatives, the skunks, mink, and otter. I have seen skulls 

 in such fearful condition that it would seem as if the animal 

 must soon succumb ; still there is no proof that the parasite ever 

 does cause death. PiUorius loivjicauda and P.frenatas are so free 

 from its attacks that it is rare to find a skull of either badl}^ 

 affected. P. noveboracensis, on the other hand, suffers so much 

 that it is hard to get perfect skulls, since many are so distorted 

 that the whole interorbital region is unfit for comparison. As 

 far as I can learn, P. longicniula occurs in larger numbers than 

 any of our weasels, while P. noneboraccnsls is apparently not an 

 abundant animal anywhere. 



1— Bioi.. Soc. Wash., Vol. X, 1890 (I) 



