1918] Swarth: The Pacific Coast Jays of the Genus Aphelocoma 407 
Coues) are matters of structure (at least such as are commonly used 
in distinguishing bird genera), of color, of eggs, and of habits. In 
Sieberocitta, as compared with true Aphelocoma, besides the obvious 
and constant color differences, the tail is shorter instead of longer 
than the wing, and the eggs are plain blue instead of double pigmented. 
The call-notes of the two are widely different. Of habit differences 
it may be noted that while Aphelocoma is relatively solitary in its 
mode of life, Sieberocitta is as markedly gregarious as the Pinon 
Jay (Cyanocephalus cyanocephalus), going habitually in closely 
assembled flocks of twenty or thirty individuals, and even nesting in 
rather loose rookeries. Another feature of Sieberocitta is its habit 
of constructing extra nests, as the Marsh Wren does. 
The point here made is that in the genus Aphelocoma there are 
these two aggregations of species and subspecies, each group dis- 
tinguished by certain features, common to all the forms therein, of 
coloration and pattern, structure, eggs, call-notes and habits. The 
two groups occur to a large extent over the same territory, where, 
however, they occupy slightly different ecologic niches, Sieberocitta 
being primarily a bird of open oak woods, true Aphelocoma, of denser 
underbrush. It seems to me that it is desirable that these two groups 
be accorded subgenerie recognition. 
If it were feasible to consider all the forms of true Aphelocoma as 
subspecies of one species, and all of Sicberocitta as of another, this 
might equally well serve to segregate them as they should be, but 
the facts hardly permit of such treatment. 
There is still another feature of the situation, namely, the relation- 
ship of the Mexican and Central American species, Aphelocoma wni- 
color; but this I am not qualified to discuss. 
In a recent paper, primarily on the status of Aphelocoma texana, 
but incidentally discussing other allied forms, Oberholser (1917, p. 
94) advocates that all of the ‘‘Aphelocoma californica group’’ be 
regarded as subspecies of one species, A. californica. This includes 
all the forms that I would restrict to the subgenus Aphelocoma, 
except A. cyanea and A. insularis. Mr. Oberholser and myself are, 
perhaps, merely stating the same thing in different ways. My main 
objection to his conception of the forms as subspecific variants is 
that much of the intergradation to which he calls attention occurs 
only through individual variation, in races that are geographically 
far apart. Individual variation in swmichrasti, in southern Mexico, 
is said to cover the difference between that form and A. californica 
