158 



Nelson, Notes on Mexican Birds. a "ii 



L April 



parts," and this description applies to the Tanagers inhabiting the arid 

 tropical mountain slopes of southwestern Mexico only including the 

 Tres Marias Islands. Temascaltepec is situated southwest of the City of 

 Mexico, on the Pacific slope of the main Cordillera. 



Piranga satigiiinolenta was described by Lafresnaye in the ' Revue 

 Zoologique' for 1839 (p- 97) as coming from 'Mexico.' It was said to 

 have the head and neck blood red with the lower surface of body cinni- 

 bar red. Tanagers with this style of coloration inhabit the humid tropi- 

 cal region of Vera Cruz and range thence south through tropical Guate- 

 mala and other parts of Central America to Chiriqui. During my field 

 work in Mexico I have found each of these birds restricted to a definite 

 faunal region, and apparently without intergrading, although further 

 work may prove them to be geographical races of the same species. 



The most striking difference between the males is the distinctly orange 

 shade of bidentata contrasted with the rosy-scarlet or red shade of sati- 

 guinolenia. The two may be distinguished by the following descriptions : 



Piranga bidentata. — Adult male : Head, neck and lower partj, includ- 

 ing under tail-coverts, rich cadmium orange, with a richer or more red- 

 dish shade on crown, throat and breast; flanks duller or more brownish; 

 feathers of back blackish brown edged with dark orange, and some- 

 times greenish yellow; rump ochraceous brown; wings and tail blackish 

 brown ; greater and lesser wing-coverts tipped with white spots, forming 

 two well defined white wing-bands; outer pair of tail-feathers tipped with 

 white for about one-third of length, mainly along inner web. Three 

 adult males from Jalisco and Sinaloa average as follows : Wing, 98 ; tail, 

 79.3; culmen, 17.3; tarsus, 21. i.' 



Adult female: The cadmium orange area of male is replaced by green- 

 ish yellow with a faint orange wash on breast. Back, wings and tail 

 grayish brown; rump brown, washed with dark greenish yellow ; outer 

 tail-feathers with white tips much smaller than on males, occupying only 

 about the terminal fifth of inner web. 



Piranga sanguinolenta. — Adult male: Head, neck and lower part 

 orange vermilion, becoming intense, flaming rosy scarlet on many spec- 

 imens ; back and rump brownish, heavily shaded with the general red 

 color; wings and tail blackish brown; two conspicuous white wing-bands 

 formed by white tips to greater and lesser wing-coverts ; outer web of 

 tertials white-spotted at tips; outer pair of tail-feathers tipped with white 

 spots about as \n P. bidentata Jlamniea. Four adult males average as 

 follows: Wing, 97.2; tail, 79.7; culmen, 16.2; tarsus, 21.4. 



Comparing the measurements of the two species it will be noted that 

 sanguinole7ita has a smaller bill and proportionately longer tarsus. The 

 females of the two species are more nearly alike than the males, but those 

 of sanguinolenta may be distinguished by their more intense coloration 

 and the small amount of white on. the outer tail-feathers. 



'All measurements are in millimeters. 



