PICID.E — THE WOODPECKERS. 529 



P. tridactylus. Dorsal region with white markings, of various amount 

 anil ilirniion ; a more or less distinct supraloral white streak or stripe, and 

 a more or less apparent nuchal band of the same. Four to six middle tail- 

 feathers entirely black ; when six, the remainder are white, with distinct 

 black bars to their ends ; when four, they are white without any black bars, 

 except occasionally a few toward the base. Sides always with Ijlack streaks 

 or markings, but they are sometimes very sparse ; crissum banded with 

 black, or immaculate; sides of the breast not continuously black. ^. 

 Crown with a patch of gamboge, amber, or sulphur-yellow, surrounded by 

 a whitish suffusion or markings. ? . Crown without any yellow, but dis- 

 tinctly streaked, speckled, or suSused with whitish (very seldom plain black). 



a. Six middle tail-feathers wholly black. Europe and Asia. 



Sides and crissum heavily barred with black (black bars about as 

 wide as the white ones). 



Back usually transversely spotted with white ; occasionally 

 longitudinally striped with the same in Scandinavian examples. 

 "Wing, 4.80 to 5.10; tail, 3.80 to 4.00; culmen, 1.20 to 1.3.5. 

 Hah. Europe ...... var. iri dactyl us} 



Sides and crissum almost free from black bars; black bars on the 

 outer tail-feathers very much narrower than the white. 



Back always (?) striped longitudinally with white. Wing, 

 4.70 to 4.75 ; tail, 3.65 to 3.90 ; culmen, 1.20 to 1.35. Hah. 

 Siberia and Northern Russia . . . var. criss oleucus." 



b. Four middle tail-featliers, only, wholly black. North America. 



Sides heavily barred with black, but crissum without bars, except 

 beneath the surface. Three outer tail-feathers without black bars, 

 except sometimes on the basal portion of the inner webs. Wing, 

 4.40 to 5.10; tail, 3.40 to 3.70; culmen, 1.10 to 1.25. 



Back transversely spotted or barred with white. Hab. 

 Hudson's Bay region; south in winter to northern border of 

 Eastern United States ..... var. am er icon us. 



Back longitudinally striped with wliite at all seasons. Hah. 

 Rocky Mountains ; north to Alaska .... var. dorsalis. 



1 Picoides tridnd>j!us, var. tridadijlus. Picus tridactylus, LiNN. S. N. 12th ed. I, 177(1766). 

 — Degland, Om. Eur. I, 161 (1849). Apternus tridactylus, Bonap. Birds (1838), p. 9. — 

 Gould, Birds of Europe, pi. ccxxxii. Picoides tridactylus, Gii.w. Picoides europceus. Less. 

 Orn. p. 217 (1831). 



^ Picoides tridactylus, var. crissolcucus. Picus crissolettcits, Brandt, Mus. Petrop. Apternus 

 crissoleiiciis, Bonap. Consp. — Reich. Syn. p. 362, No. 836 ; pi. dcxxxi, f. 4197, 4198. Picoides 

 crissolcucus, Malh. Monog. Pic. I, 180. " Apternus kamtchatkeiisis, BoxAP." — Malh. Monog. 

 Pic. I, 180 (in synonomy). Apternus tridactylus, Mus. de Mayence. — Pallas, Zoogi'. Ros. 

 As. 1, 415. 



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