472 NORTH AMERICAN BIRDS. 



"Western United States, east to Rocky Mountains; south 

 through central and western Mexico in winter. 



. V. gilvus swainsoni (BAIRD). 



Western Warbling Vireo. 1 



i*. Wing with two distinct white bands across tips of middle and greater 



coverts. (Subgenus Lanivireo BAIRD.) 



c 1 . No spurious primary ; loral streak, orbital ring, chin, throat, and breast 

 yellow ; top of head olive-green. 



Posterior under parts white ; rump, upper tail-coverts, and scapu- 

 lars ash-gray; hind-neck and back olive-green; tertials broadly 

 edged with white ; length 5.00-5.85, wing 3.00-3.20, tail 2.00- 

 2.30. Nest in woods, usually at a considerable height from 

 ground. Eggs .79 X -58, usually more heavily spotted than in 

 other species. Hab. Eastern United States, west to edge of 

 Great Plains; south, in winter, to Costa Rica. 



628. V. flavifrons VIEILL. Yellow-throated Vireo. 



c*. A more or less distinct spurious primary ; loral streak, orbital ring, 

 chin, throat, etc., white ; top of head ash-gray or plumbeous (more 

 brownish in winter). 



d 1 . Spurious quill minute (much shorter than exposed culmen) ; hind- 

 part and sides of neck olive-green, like back and scapulars ; 

 chest and breast (especially sides of the latter) strongly washed 

 with sulphur-yellow. (Otherwise much like F. solitarius.') 

 Wing 3.05, tail 2.20, bill from nostril .30, tarsus .72. Hab. 

 Highlands of Guatemala (Coban, Vera Paz). 



V. propinquus (BAIRD). Vera Paz Vireo. 1 



cP. Spurious quill well developed (much longer than exposed culmen) ; 

 hind-part and sides of neck grayish, like top of head and ear- 

 coverts ; chest and breast without yellow tinge. 

 e 1 . Sides and flanks conspicuously olive or olive-green, distinctly 

 tinged with yellow; back, rump, and upper tail-coverts olive- 

 green. (Young in first winter with anterior upper parts 

 dull grayish brown, the lower parts dull buffy white, the 

 general aspect quite different from full adult plumage.) 

 /*. Smaller (wing not more than 3.00, tail rarely more than 



2.20). 



g l . Back, etc., brighter olive-green, more abruptly con- 

 trasted with plumbeous-gray of head and neck, 

 the latter deeper and clearer ; gray of cheeks more 

 abruptly contrasted with white of throat ; sides 

 and flanks usually more strongly tinged with 



l Vireo iwaintoni BAIRD, B. N. Am. 1858, 33ft (in text). Vireo gilvut, var. irainoi COUES, Key, 1872, 121. 

 * VireotyMa propinqtta BAIRD, Review Am. B. i. May, 1866, 348. 



This it either a very distinct species or else, as suggested by Messrs. SALTIN & GODMAN (Biol. Centr.-Am., 

 Avet, i. p. 197) a hybrid between F. lolitariut and 



