186 bulletin: museum of compaeatiye zoology. 



Geothlypis trichas arizela Oberh. 

 Oberholser's Yellow-throat. 



Geothlypis trichas (not Tardus trichas Linnaeus) Baird, Rev. Amer. Birds, pt. L 



1865, 220, 222, part (Cape St. Lucas). Beldixg, Proc. U. S. Nat. Mus., V. 



1883, 536 (Cape Region). 

 Geothli/pls trichas occidentaits (not of Brewster), Bryant, Proc. Calif. Acad. Sci., 



2d ser., IL 1889, 310 (Cape Region). 

 G.[eothlijpis] trichas occidentalis (not of Brewster) Bryant, Zoe, IL 1891, 192 



(San Jose del Cabo). 

 Geothh/pls trichas arizela Oberholser, Auk, XVI. 1899, 256-258 (orig. descr. ; type 



from Fort Steilacoom, Wash. ; La Paz; San Jose' del Cabo). 



The large series of autumnal specimens of this form collected by Mr. Frazar^ 

 represents very fully the winter plumages of the adult and yoimg of both 

 se.ves. 



The adult male in autumn has the crown, nape, back, wing coverts, under 

 tail coverts, and sides of body strongly tinged with cinnamon (nearly pure 

 cinnamon brown on the crown and flanks) ; the black feathers of the mask 

 tipped with grayish on the auriculars and sides of the neck, with mixed gray 

 and cinnamon on the forehead ;2 in every other respect it is similar to the 

 male in spring. 



The young male in autumn differs from the adult at the same season in 

 having the black of the mask restricted to a broad malar stripe and in possess- 

 ing some concealed spotting at the base of the feathers of the forehead. The 

 upper parts, also, show less cinnamon, and the entire top of the head is nearly 

 concolor with the back. The yellow of the breast is sometimes tinged with 

 saffron, but this is also the case with some apparently mature birds. 



The adult female in autumn is rather more olivaceous above than are speci- 

 mens of the same sex taken in spring, and the throat and breast are of a deep 

 oclire yellow tinged with saffron. The forehead is suffused with cinnamon as 

 in the spring female. 



The young female in autumn has the entire under parts nearly uniform 

 clayey buff, lightest on the middle of the abdomen, slightly brownish on the 

 flanks. The upper parts are plain, dull, grayish olive, nearly uniform every- 

 where, but with a slight tinge of cinnamon on the forehead. In some speci- 

 mens the breast is suffused with dull yellowish, but none show any yellow on 

 the throat. The tint of the under parts varies considerably with different 



1 It is possible that some of tiie immature Yellow-throats in this series are refer- 

 able to G. t. scirpico/n, while otiiers may be G. t. simwsa, but both these forms are 

 said by their describer to be "permanently resident" in California (see Grinnell, 

 Condor, IIL 1901, 65). 



2 In a very few birds there is no trace of this light tipping, the mask being quite 

 as pure black as in spring. 



