'SS3-] Allen and Brewster on Colorado Birds. Ifg 



Geothlypis trichas occidenialis var. nov. Ch. subsp. Similis G. tri- 

 chcB sed Cauda longiore ; colore supra pallidiore et flaviore ; colore infra 

 magis flavicante et extento ; alba striga in pileo latiore et puriore. 



$ adult (No. 5550, Coll. W. B., Truckee River, Nevada, May 4, 1881). 

 Upper parts nearly uniform pale yellowish-olive, with a tinge of brown 

 on the occiput; throat, jugulum, breast, anterior portion of abdomen, 

 and under tail-coverts rich, pure yellow; sides of body warm ochraceous 

 brown strongly tinged with yellow; middle of abdomen anteriorly creamy 

 white; a black mask on the front and sides of the head bordered 

 behind by a broad Band of creamy white, slightly tinged with bluish; 

 much concealed yellow on the feathers of the ci-own. 



Dimensions: Wing, 2.32; tail, 2.30; culmen, .55. 



Habitat: Pacific and Middle Provinces of the United States. 



The difFei-ences which distinguish this race from trichas proper, 

 although somewhat difficult of description, are readily appreciable upon 

 a comparison of specimens ; they may be briefly summed as follows : 

 Occidenialis is somewhat larger than trichas and its tail is disproportion- 

 ately longer. Its upper parts are always paler and usually yellower; the 

 yellow of the under parts is decidedly richer and purer, and extends 

 much further down on the' abdomen, frequently tinging nearly all of the 

 body beneath ; the flanks are paler and more ochraceous ; the white of 

 the head purer and generally broader. 



I have not seen var. melanojbs of Mexico but judging from descriptions 

 the present face approaches it rather more closely than it does trichas. 

 A decided approach is furnished by a sjpecimen from Cienega Station, 

 Arizona (No. 5906), which is even yellower above than my type of occi- 

 denialis, while the yellow of the under parts extends over nearly all the 

 abdominal region and strongly tinges the flanks. This bird agrees very 

 closely with Baird's description of G. nielajiops but is considerably 

 smaller. In my paper on the Arizona collection I referred it to G. trichas, 

 but I am now inclined to consider it an intermediate between the present 

 race, occidetitalis, and melanoj)s-oi Mexico. 



31. G-eothlypis macgillivrayi. Macgillivray's War- 

 bler. — First seen May 4. Soon became frequent, and continued 

 more or less common in willows along creek bottoms till the end 

 of the month. 



33. Icteria virens. Yellow-breasted Chat. — First 

 observed May 13 ; others seen and heard on following days. 



33. Myiodioctes pusillus pileolatus. Black-capped 

 FLYCATCHiiSTG Warbler. — ^ First seen May 12; of frequent 

 occurrence later in willow thickets along streams. 



34. Setophaga ruticilla. Redstart. — First seen May iS. 

 Not common. 



35. Pyranga ludoviciana. Loulsiana Tanager. — Ar- 

 rived in large numbers May I3, and continued common. 



