414 University of California Publications in Zoology  [Vou. 17 
Range.—The coast region of northern California, west from Mount Diablo 
and the coast ranges. North to Humboldt Bay, south to the Golden Gate and 
the east side of San Francisco Bay. 
Specimens examined from the following localities: Alameda County—Oak- 
land, 1; Piedmont, 1; Berkeley, 9. Contra Costa County—Walnut Creek, 5; 
Mount Diablo, 3; Danville, 5. Marin County—Mailliard, 1; Inverness, 3; 
Nicasio, 4; San Geronimo, 3. Sonoma County—Sonoma, 1; Stony Point, 2; Free- 
stone, 1; Guerneville, 10; Santa Rosa, 1. Mendocino County—Mendocino City, 1; 
Mount Sanhedrin, 2; Bald Hill, 1; Sherwoods, 2. Humboldt County—Arcata, 1. 
Total 57. 
Distinguishing characters.—Of large size and dark coloration. In color closely 
similar to A. ec. californica, but size measurably greater throughout. In measure- 
ments oocleptica is equal to the maximum of immanis, from which subspecies it 
is distinguished by its dark coloration. Differs from hypoleuca both in greater 
size and much darker color. 
No. 6001 (Mailliard coll.), male, Nicasio, Marin County, October 29, 1894. 
Blue areas, deep cadet blue; dorsum, sepia. 
Remarks—It was an unexpected development of the present study 
that there should be disclosed the presence of an additional race of 
Aphelocoma within the state. The specimens at hand, however, are 
ample for the establishing of this subspecies, the characters exhibited 
being clearly defined, and the territory occupied by the form capable 
of being outlined with a fair degree of accuracy. While in the com- 
bination of characters possessed oocleptica might be considered as 
an intergrade between californica and immanis, still it is not truly 
intermediate between the two. It has assumed the distinetive char- 
acters of large size (equal to the pale colored immanis), and dark 
eoloration (as in the small sized californica), each to the fullest degree. 
It is the combination of these two features that distinguishes the race. 
There is more evident appearance of intergradation between 
oocleptica and immanis, than between the former and californica. 
Of the last mentioned form, examples from points immediately south 
of San Francisco Bay (closely approaching the range of oocleptica) 
are indistinguishable from specimens from southern California, there 
being no appreciable increase in size. On the other hand, at points 
where the ranges of oocleptica and immanis come together (as in 
parts of Marin and Sonoma counties), individuals exhibiting various 
degrees of intergradation between the two are of frequent occurrence. 
In southern Marin County somewhat similar conditions prevail in 
Aphelocoma as have already been noted of other variable groups in 
the same region as Psaltriparus (Swarth, 1914, pp. 5138-515) and 
Thryomanes (Swarth, 1916, p. 66), namely, the frequent occurrence 
of individuals evincing a marked tendency toward the appearance of 
