140 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



KEY TO THE SUBSPECIES OF DRYOBATES SCALAEIS, BASED ON ADULT MALES. 



u. Outermost long rectrix (the second) with black spots or bars on whole of both vanes.* 

 b. Lower surface darker, more smoky. 

 c. Larger (wing usually more than 100 mm.); sides of breast streaked with black; 

 black bars on upper parts wider; black postocular and malar stripes wider, 

 the latter reaching bill. 

 d. Somewhat larger (wing averaging 104.4 mm.); lower surface darker; black 

 bars on back broader; postocular stripe wider . . . .Dryobates scalaris bairdi. 

 d' . Somewhat smaller (wing averaging 102.4 mm.); lower surface lighter; black 

 bars on back narrower; jjostocular stripe narrower. 



Dryobates scalaris centrophilus . 



(/. Smaller (wing less than 100 mm.); sides of breast spotted with black; black 



bars on upper parts narrower; black postocular and malar stripes narrower, 



the latter not reaching bill. 



d. Larger (wing more than 93 mm.); black bars on basal part of exterior vane 



of outermost long rectrix (the second) averaging larger, never absent. 



Dryobates scalaris scalaris. 



d' . Smaller (wing usually less than 93 mm.); black bars on basal part of exterior 



vane of outermost long rectrix (the second) reduced to spots, and averaging 



smaller, occasionally absent Dryobates scalaris ridgwayi. 



y. Lower surface lighter, less smoky, 

 c. Larger (wing usually over 100 mm.; averaging more than 101 mm.). 

 d. Upper parts darker (the white bars narrower, the black bars broader); sides 

 • of breast more often streaked; size somewhat larger. 



Dryobates scalaris cactophilus. 

 d' . Upper parts lighter (the white bars wider, the black bars narrower); sides 

 * of breast less often streaked; size somewhat smaller. 



Dryobates scalaris sympleclus. 

 (/. Smaller (wing under 100 mm.; averaging less than 98 mm.). 



d. Postocular and malar stripes wider, the latter always reaching bill; size 

 smaller (wing averaging 89.1 mm.); black bars on back somewhat narrower; 

 primary coverts with somewhat less white; lower parts less heavily spotted. 



Dryobates scalaris parvus. 



d' . Postocular and malar stripes narrower, the latter usually not reaching bill; 



size larger (wing averaging 96.5); black bars on back somewhat wider; 



primary coverts with somewhat more white; lower parts more heavily 



spotted Dryobates scalaris percus. 



a' . Outermost long rectrix (the second) with black spots or bars wanting on most of 

 basal half of exterior vane. 

 h. Lower surface much darker, 

 c. Larger (wing more than 90 mm.); sides of breast streaked with black; primary 

 coverts with more white. 

 d. Back and scapulars darker, the black bars wider, the white bars narrower; 

 size decidedly greater (wing averaging more than 100 mm.); malar stripe 

 not obsolete at base of bill; black bars on tail generally broader; streaks 



on sides of breast rather wider Dryobates scalaris agnus. 



(?■'. Back and scapulars lighter, the black bars narrower, the white bars 

 wider; size decidedly smaller (wing averaging less than 100 mm.); malar 

 stripe nearly always obsolete at base of bill; black bars on tail generally 

 narrower; streaks on sides of breast rather narrower. 



Dryobates scalaris sinaloensis. 



I In Dryobates scalaris ridgwayi these are occasionally wanting on proximal portion of outer vane. 



