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.