Woodpeckers 223 
outer pair rudimentary and concealed, so that there 
appear to be only ten; these are very stiff and strong 
with rigid shafts and pointed tips. Tarsi scutellate im 
front, reticulate behind ; toes four or sometimes three, 
the hallux being occasionally lost, the fourth toe 
reversed and pointing backwards alongside the first or 
hallux. Tongue very long, worm-like and extensile, and 
actuated by a special arrangement of the hyoid 
muscles and bones. 
Family PICIDA, 
All the North American Woodpeckers are included 
in this family. 
Key oF THE GENERA. 
A, Outer hind toe longer than the outer front toe. 
a. Four toes. 
a! Plumage black and white, red on the crown only, no yellow. 
Dryobates, p. 223. 
bt Plumage black, white, yellow and red. Sphyrapicus, p. 228. 
b. Three toes only ; crown with yellow, not red. Picoides, p. 227- 
B. Outer hind toe about equal to the outer front toe. 
a. Back red, black and white in masses. Melanerpes, p. 233. 
b. Back glossy green with a grey nuchal collar. Asyndesmus, p. 235. 
ce. Back cross-barred with black and white. Centurus, p. 237. 
C. Outer hind toe distinctly shorter than outer front toe. 
a. Head red-crested, size large, wing over 8. Phlaeotomus, p. 232. 
b. Head not crested; belly with round, black spots. 
Colaptes, p. 238. 
Genus DRYOBATES. 
Bill stout and straight, about equal to the head; a sharply defined 
ridge on, the culmen and on a groove on either side of the upper mandible; 
wing long and pointed, the outer primary quite short; four toes, the 
outer posterior (fourth) longer than the outer anterior (third) ; plumage 
black and white, the wings black with white spots; red on the head 
in the male only. 
A considerable genus with six species in the United States. 
