PICID^ — THE WOODPECKERS. 529 



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

 and direction ; a more or less distinct supraloral wliite 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 black 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. 9- Crown without any yellow, but dis- 

 tinctly streaked, speckled, or suffused 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 1.35. 

 Hab. Europe ...... var. tridactyhis} 



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. Hab. 

 Siberia and Northern Russia . . . var. crissoleucus? 



b. Four middle tail-feathers, 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. americanus. 



Back longitudinally striped with white at all seasons. Hab. 

 Rocky Mountains ; north to Alaska .... var. dor salts. 



1 Picoides tridactylns, var. tridactylus. Picus tridactylus, Linn. S. N. 12th ed. I, 177(1766). 

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

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

 Orn. p. 217 (1831). 



2 Picoides tridactylus, var. crissoleucus. Picus crissoleucus, Brandt, Mus. Petrop. Apternus 

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

 crissoleucus, Malh. Monog. Pic. I, 180. " Apternus kamtchatkensis, Bonap." — Malh. Monog. 

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

 As. I, 415. 



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