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The Arizona Race of the Sulphur-bellied Flycatcher

A. J. Rossem

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The writer has for some years suspected the advisability of providing with a name that portion of the Sulphurbellied Flycatcher population which breeds in the extreme northwestern part of the range of the species. Material which subsequently has come to hand has served further to emphasize the first impressions, and the Arizona race is therefore named as

Myiodylurstes luteiventris swarthi, subsp. nov. Arizona Sulphur-bellied Flycatcher.

Type.-Male adult; no. 8986, collection of Donald R. Dickey; Huachuca Mountains, Arizona; September 8, 1913; collected by A. B. Howell; original no. 2656.

Subspecific characters.-Resembles luteiventris luteiventris Sclater, of southern Mexico and Central America, but under parts paler yellow; streaking of under parts less conspicuous and averaging narrower, particularly on flanks; upper parts paler with edgings of feathers grayer (less yellowish) buff; edgings on wing coverts whiter and usually broader; cinnamon rufous of lower rump, upper tail coverts, and tail paler.

Range.-High lnountains of southern Arizona and probably adjacent parts of Mexico.

Remarks.-The Arizona race is named with full appreciation of the extraordinary individual variation to which this species is subject. The differences between the two races are fully as prominent in the juveniles as in fresh adults, but are obscured in very worn post-breeding adults. Mr. Ridgway (Birds of North and Middle America, part 4, 1907, pp. 656-657) comments on the heavy streaking and smaller size of extreme southern birds, but in the em>luteiventti from Vera Cruz and luteiventris of Central America, or between luteiventris and swarthi. In coloration the Vera Cruz and Yucatan birds are variously intermediate, but on the average fall unmistakably with the richly colored and heavily streaked Central American series.

Material necessary in the above work is gratefully acknowledged from the American Museum of Natural History, Dr. Louis B. Bishop, Mr. Donald R. Dickey, Mr. J. E. Law, the Museum of Vertebrate Zoology, and above all from Mr. Harry S. Swarth whose splendid series of personally collected Arizona specimens has confirmed the desirability of separating the Arizona race.

Specimens examined.-Myiodynastes luteiventris luteiventris: Mexico: Vera Cruz (Jalapa, 2, Orizaba, 1) ; Yucatan (“Yucatan”, 1, Calotmul, 1). Salvador: San Salvador (San Salvador, 4, Volcan San Salvador, 1) ; La Libertad (Sitio de1 Niiio, 1) ; San Miguel (Lake Olomega, 6, Volcan San Miguel, 1). Costa Rica: Guanacaste (Las Caiias, 1). Myiodynastes luteiventris swarthi: Arizona (Chiricahua Mountains, 6, Huachuca Mountains, 18).

Pasadena, California, December 18, 1926

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