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 208 THE CONDOR Vol. XXIV ties. Breeding specimens typical of both artemisiae and obscurus are at hand from Death Valley, the Panamint MOuntains, and Independence. To add to the complexity of the material from this region, several of the intergrades (pos- sibly hybrids would be a better term) are practically indistinguishable from californicus, and were they taken in the San Joaquin Valley, would pass as examples of that form. In this regard the present case is clarified, however, by the exact analogy detected some years ago among the horned larks by Dr. It. C. Oberholser(). Briefly, the case may be summed up as follows: Where the two forms come together, a combination of their characters has resulted in a more or less typical reduplication, in certain individuals, of the characters of a third well-defined race occupying a distant and delimited area. Molothrus ater californicus, subsp. nov. California Cowbird DIAGNOSTIC CHARACTERS: FEMALES: Compared with Molothrus ater obscu- rus, size larger, tail proportionately shorter, and tarsi and feet much heavier; coloration darker, especially below (more slaty), and streaking sharper and more conspicuous. Compared with Molothrus ate artemisiae, size smaller; streaking of under parts narrower. MALES: The proportion of wing to tail is practically the same in the males of all three races, but the larger size, heavier tarsi and feet, together with the greater bill size of californicus will serve as distinguishing characters when compared withobscurus; the smaller size, par- tieularly of these parts, will differentiate the race with equal facility from artemisiae. TYPE: Female 'adult, H 707, collection of Donald R. Dickey; Buena Vista Lake, Kern County, California; May 20, 1920; collected by Donald R Dickey and A. J. van Rossem; original number A. J. van R. 5366. RGE: In summer, the San Joaquin Valley of California, from the ex- treme southern end north at least to northern Merced County, and possibly north to include the Sacramento Valley; also east in favorable localities to the Sierra foothills, as at Weldon, Kern County, and Snelling, Merced County. Wandering west and south in the fall to Ventura County (Oxnard), and Santa Barbara County (Carpinteria)., and in spring at least to Los Angeles County (El Monte). Specimens examined from the following localities: Kern County: Buena Vista Lake, Bakersfield, Weldon; Merced County: Snelling; Fresno County: Mendora; Santa Barbara County: Carpinteria; Ventura County: Oxnard; Los Angeles County: E1 Monte. REMARr:S: We have selected a female as the type because the differences between the several forms are (as is the ease with certain races of Agelit.s) more pronounced and uniform among individuals of this sex than among the males. This form is apparently resident in the southern San Joaquin at all seasons of the year. In September, 1921, and in January, 1922, the junior writer found cowbirds almost, if not quite, as common in the vicinity of Buena Vista Lake as during the summer. No specimens were taken at these times, because for some reason the birds were extremely shy. A large series of fall, winter, and spring specimens taken outside the San Joaquin Vglley fails to disclose any birds re- ferable to this race, except those mentioned above. Intergradation with obscurus takes place in the northern part of the San Diegan District, for breeding birds U) Proc. U.S. Nat. Mus., -4, 1902, pp. 802-803.