1926] Swarth: Birds and Mammals from the Atlin Region ‘9

would place as subspecies, D. f. fuliginosus, D. f. sitkensis, D. f. sierrae, and D. f. howardi. The differences between the obscurus and fuli- ginosus 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 obscurus and fuliginosus, but these are all assertions of the most casual nature, with no detailed information accompanying them.

Fig. D. Tails of Dendragapus obscurus obscurus; % natural size. a, immature female, during first year (M.V.Z. no. 32051); b, 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 flemingi, 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.