PICID.*; — THE WOODPECKERS. 493 



much curved to the acutely pointed (not truncate) tip. The commissure 

 considerably curved. Hill without any ridges. The nostrils hroadly 

 oval, and much exposed. Anterior outer toe longest. 



The preceding diagnoses will serve to distinguish the three groups suf- 

 ficiently fov our present purposes ; tlie bill being strongest in the I'icina; and 

 best fitted for cutting into trees by its more perfect \vedge-shai)e, with 

 strengthening ridges, as well as by the lateral bevelling of both mandibles, 

 which are nearly ei[ual in thickness at the base, and with their (jutlinos 

 nearly straight. The lateral ridge is prominent, extending to the edge or 

 end of the bill, and overhangs the nostrils, which are narrow and hidden. 

 Tiie Centurcce and the Culaptccv have the upper mandible more curved 

 (the commissure likewise), the lower mandible smaller and weaker, the 

 bill with little or no lateral bevelling. The nostrils are broadly oval and 

 exposed. In the former, however, there is a distinct lateral ridge visible 

 for a short distance from the base of the bill ; while in the other there 

 is no ridge at all, and the mandible is greatly carved. 



In all the species of North American Woodpeckers, there is more or less 

 red on the head in the male, and frequently in the female. The eggs of all 

 are lustrous polished white, witliout any markings, and laid in hollow trees, 

 upon a bed of chips, no material being carried in for the construction of the 

 nest. 



Section PICE^. 



With the common characters, as already given, there are several well- 

 marked generic groups in this section of Woodpeckers which may be arranged 

 for the United States species as follows : — 



A. Posterior outer toe longer than the anterior outer one. (Fourth toe longer 

 than third.) 



a. Lateral ridge starting above the middle of the base of the bill, and 



extending to the tip. 



1. Campephilus. Lateral ridge above the midd'o of the lateral profile 

 of the bill when opposite the end of the nostrils, which are ovate, and 

 rounded anteriorly. Bill much depressed, veiy long ; goiiys very long. 

 Posterior outer toe considerably longer than the anterior. Primaries 

 long, attenuated towards the tip. Spuriof? quill nearly half the second. 

 Shafts of four middle tail-feathers rem:. ]:ably stout, of equal size, and 

 abruptly very much larger than the others ; two nii<ldle tail-feathers 

 narrower towards bases than towards end.' A pointed occipital crest. 



2. Picus. Later.al ridge in the middle of the lateral profile opposite the 

 end of the nostrils, wliieli are ovate and sharp-pointed anteriorly. Bill 

 moderate, nearly as broad as high. 



' A ehavactcr cnmmon to all the iiiciiilicrs of tlic genus, and distinguishing tlinni from the 

 sjii'ui'S iif cvc-.-y other ; tliia peenliiir fi>riii of the niidille tiiilfeatliers is oaused iiriiu'ipidly by ft 

 foliii:i;,' nf the webs lownwarit, almost iipiiiist eaeli other. Tlie under .surface.s of the shafts have 

 a vi'iy deep groove their wliole length, which is seen in no other gemis. 



