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 64 THE CONDOR Vol. XIX distinct species, and this circumstance but serves to emphasize the wide differ- ence in appearance in the sexes; while the fact that in a species with such marked sexual distinctions the juvenal plumages of male and female, respectively, exhibit essentially the same differences, renders it unique among the woodpeckers of North America, at least. In fact there are very few birds of any order that fall within this category. The female thyroideus exhibits the widest departure from the mode of pat- tern and coloration as seen in the genus Sphyrapicus at the present time. It is unique in all the phases of specific, age, or sex variation within the genus in the total absence of red coloration and of white upon the wing coverts. This, how- ever, does not mean that the female of thyroideus exemplifies the farthest ad- vance, the greatest departure, from the ancestral coloration in the genus. On the contrary, the fact that it is in the juvenal plumages of the several other forms of Sphyrapicus, all with greater or less development of barring upon the body, that there is found the closest resemblance to the female thyroideus, suggests the possibility of the latter being in rather a primitive stage. The observed develop- ment of the black breast patch supports this idea. In the juvenal plumage there is no indication of this marking. In the adult birds (meaning by this all that have passed beyond the juvenal stage, it being usually impossible to distinguish between fall iramatures and adults), there are one or two at hand in which the barring on the breast is 'no heavier and no more confluent than on other parts of the body, in most specimens there is more or less indication of a black patch, and in a lesser number of individuals this marking is largely developed and of a glossy black color. In one skin from the Warner Mountains, California (no. 14197, Mus. Vert. Zool.), the extension of the black area is so great, and the yel- Jow of the belly so intense, that, aside from the absence of red on the throat, this specimen, as far as the under parts are concerned, is hardly to be distinguished from a male bird. Variation in the male thyroideus appears principally in the amount of white spotting on the outer webs of the primaries, amount of concealed white in the int;rscapular region and the character of the markings on the flanks, in all of vhich there is no correlation of appearance with locality. Some young birds sho.w more white dorsally than any adults, the streakings being but partly con cealed and covering the whole back, but on the other hand there are some with the upper parts of as "solid" black as any adults. In some juvenal males the head, and even the breast, is heavily mottled with whitish. In the adults there is frequently enough white streaking dorsally to show through upon the slightest disarrangement of the feathers. In the juvenal male the flanks seem to be inva- riably barred; in the adult, though the effect is usually of streakings or elongat- ed V-shaped markings, occasional individuals have as definitely barred flanks as any of the females. Specimens examined: Sphyrapicus thyroideus thyroideus California. Riverside County: San Jacinto Mountains, 5. San Bernardino County: San Bernardino Mountains, 13. Los Angeles County: Mount Wilson, 3 (winter); Pasadena, 1 (winter); Los Angeles, 1 (winter). Ventura County: II-ead of Piru Creek, 1 (winter). Tulare County: localities in Sierra Nevada, 17. Fresno County: Horse Corral Meadow, Sierra Nevada, 5. Inyo County: Cotton- wood Lakes, 2. Yosemite National Park, 16. Mono County: Walker Lake, 1. Eldorado County: Hope Valley, 1; Gilmore Lake, 1; Mount Tallac, 1; Meyers, 1.