478 



SYSTEM A TIG SYNOPSIS. — PICABIM — PICIFOBMES. 



length of the outer hind toe, are characters which diminish or are lost together as we pass from 

 the Ivory-hill extreme to the Flicker end of the series. The claws are always large, strong, 

 sharp, and much curved ; the feet do not present striking generic modifications, except in the 

 three-toed genus Picofides; the length of the outer hind toe is the most variahle factor. The 

 wings are specially noteworthy, for the shortness of the coverts, in exception to the Picarian 



Fig. 329. — Ivory-billed Woodpecker, i nat. size. (From Brehm. ) 

 rule ; and the shortness of the first primary, which may fairly he called spurious ; but these 

 points and the remarkable character of the tail have been already mentioned. This member 

 offers indispensable assistance in climbing, when the stiff strong quills are pressed against the 

 tree, and form a secure support. To this end, the muscles are highly developed, and the last 

 bone {vomer or pygostyle) is large and peculiar in shape. Woodpeckers rarely if ever climb 

 head downward, like Nuthatches, nor are the tarsi applied to their support. 



