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PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



lateral groove distinct for half the length of the bill; culmen decidedly 

 but gently curved from the base ; gonys nearly straight, and about half 

 as long as the culmen. Nostrils broad, elliptical, situated about mid- 

 way between the culmen and tomium, and only partly concealed by the 

 frontal tufts. Anterior outer toe a little longer than the posterior, the 

 inner anterior toe decidedly shorter, and the inner hind toe only about 

 half its length. Wings long and broad, third to fifth primaries longest, 

 the first equal to the sixth to the ninth. Tail about two-thirds as long- 

 as the wing, gradnated, the feathers (except the outer) rather abruptly 

 attenuated at ends. Colors, banded with black and white, or yellow, 

 above, with more or less of the pileum scarlet in the male; below plain, 

 the abdomen tinged with red, orange, or yellow in most species. 



The so-called genus Centiirus is scarcely more than an artificial division 

 of Melanerpen, distinguished from the typical section of that genus chiefly, 

 if not only, by a difl'erent system of coloration, which characterizes njost 

 of the species. Even in this respect, however, the intergradation of 

 the two sections is so complete that certain species (notably Zehrapicus 

 imclicrani of Malherbe) may, with almost equal propriety, be referred to 

 either group. The species referred toTias usually been included in (Jen- 

 turns ; but after careful consideration of the question, I have concluded 

 to place it in 3Ielanerpes, as being more closely related to certain species 

 of that group than to any of the species of Centurus as here restricted. 

 Its nearest allies are undoubtedly the Melanerpes chrysuuchen of Salvin, 

 which it resembles very closely, and ^'•Picus^'' { = Melanerpes) flavifrons 

 of Vieillot, and it may well be placed with them, while if allowed to re- 

 main in Centurus its position would be that of an isolated or aberrant 

 species*. 



Following is a list of the forms recognized in this review, with the 

 number of specimens of each which have been examined in connection 

 with the preparation of this paj)er: 



