No, 11, NORTH AMERICAN FAUNA, June, 1896. 



SYNOPSIS OF THE WEASELS OF NORTH AMERICA, 



By C. HART MERRIAM. 



The present synopsis includes the one ferret and all of the weasels 

 yet discovered in North America north of Panama. Of the true weasels 

 (subgenus Ictis ) no less than 22 species and subspecies are here recog- 

 nized, 11 of which are described for the first time. 



Until very recently the group has been in a state of chaos, but now,, 

 thanks to Outram Bangs's excellent paper entitled <A review of the 

 weasels of eastern North America,' 1 the obscurity that lias so long 

 surrounded our eastern species has been cleared away and the task of 

 revising the whole group is rendered comparatively easy. Additional 

 material is needed from certain parts of the West, particularly from 

 southeastern Alaska and the middle and northern parts of the Great 

 Basin, and much remains to be learned respecting the extent to which 

 jtntergradation exists between allied forms having contiguous ranges. 



Excepting the circurnpolar type, represented in America by the weasel 

 of the barren grounds (Putorius arcticus nob.), and in Eurasia by the 

 closely related P. erminea, the weasels of North America fall naturally 

 into two groups, characterized by important cranial differences, and 

 having complementary geographic ranges. The first is a boreal group 

 comprising five forms: richardsoni, alascensis, cicoynani, streatori, and 

 rixosns, the southernmost of which (cicognani) reaches only the northern 

 United States. The other is an austral group comprising tliefrenntttn 

 and longicauda series and including P. peninsiilcc, of Florida. Of this 

 series only a single species (P. arizonensis) reaches the lowermost of the 

 boreal zones, and this only in the mountains. 



Between these two groups are two very interesting species, novebora- 

 censis and Iropicnliss the former inhabiting the eastern United States, 

 the latter the tropical belt of Mexico. Mr. Bangs has already shown 

 that the female of P. noveboracensis resembles P. cicognani, while the 

 male resembles P. longicauda. The case of P. tropicalis is exactly 

 parallel, the female resembling ctcognani, while the male resembles 

 frenatus. 



1 Proc. Biol. Soc. Washington, X, pp. 1-24, Feb. 25, 1896. 



