1926] 



Swarth: Birds amd Mammals from the Atlin Region 79 



would place as subspecies, D. /. fuliginosus, D. f. sitkensis, D. f. sierras, 

 and D. f. howardl The differences between the oiscurus and fidi- 

 ffinosus aggregations are trenchant ones and I have seen no doubt- 

 ful specimens, no " intergrades, " from regions where the two come 

 closest together. There are various statements in literature affirming 

 the existence of intergradation between oiscurus and fuliginosus, but 

 these are all assertions of the most casual nature, with no detailed 

 information accompanying them. 



Fig. D. Tails of Dendragapus oiscurus ohscurus; % natural size, a, immature 

 female, during first year (M.V.Z. no. 32051) ; &, adult male, in second year or 

 older (M.V.Z. no. 45556). 



In this connection it is pertinent to note conditions at Log Cabin, 

 on the east slope of "White Pass, about on the boundary between the 

 ranges of fuliginosus and flemxngi, where Brooks hoped to collect 

 specimens of grouse that would have bearing on this problem. He, 

 himself, found no Dendragapus there, and he was told by residents 

 that none occurred in that stretch of country. 



