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80 Uniwersity of California Publications in Zoology [Vou 30

As between the two aggregations, obscurus and fuliginosus, besides
color differences and besides the shape of the tail, so markedly con-
trasted in the closely adjacent northern subspecies, account must be
taken of the call-notes of the male birds, which are so radically different
as to indicate a wide divergence and one of long standing, a specific
difference. The reverberant, wooden call of an old ‘‘hooter’’ (Den-
dragapus fuliginosus) is the same from Alaska to southern California,
a sound that carries a half-mile or more, and a very different call
from the subdued tooting of the Richardson grouse and its allies.
Complementary to this, the relative development of a part of the hoot-
ing apparatus, the naked skin on the sides of the neck, is another dif-
ference between the two forms (see Brooks, 1912, p. 252; 1926, p. 283).

It looks as though in all the earlier studies of these grouse the
presence of a terminal gray band on the tail alike of obscurus and of
fuliginosus was allowed to outweigh all other features of resemblance
or dissimilarity between the several forms. Aside from this, an adult
male of obscurus is very closely similar to an adult male richardson.
The tail of an adult male obscuwrus at hand, from Colorado, is nearly
as square as in richardsoni, not rounded as in fwliginosus. The
rectrices of obscurus, however, are not markedly truncate.

In years past richardsonii has sometimes been regarded as a species,
distinet from the several other forms of ‘‘blue grouse,’’ all regarded
as subspecies of D. obscurus, but study of a map outlining the distri-
bution of the races will show how illogical such division would be
(see fig. A).

It is curious to what an extent certain of the characters of
richardson parallel the distinguishing features of Canachites frank-
lint. This grouse (which is currently regarded as a species, distinct
from other forms of Canachites) has developed the same square-tipped
tail with broad, truncate feathers, and, besides this striking resem-
blance, the distribution of the Franklin grouse is almost the same
as in the Richardson grouse; almost, but not exactly, for northward
the range of Canachites franklinii extends well within the territory
of Dendragapus o. flemingi. In the northern portion of its range,
D. o. flemingi is accompanied by Canachites canadensis osgoodi.

In differentiating the several subspecies of ‘‘blue grouse’’ (both
species), shape and markings of the tail are useful characters, but to
ascribe proper weight to these variations an understanding is necessary
of the development of the individual bird, of the stages gone through
to reach maturity, as previously indicated in this paper. In both sexes