300 NORTHERN ZOOLOGY. 



PICIAN.E, 



or true Woodpeckers, the only perfect assemblage of forms in the whole circle. 

 The annexed table will explain the circular succession of the five genera : — 



Analogies. 1. Typical group. Genera. 



{Bill perfectly wedge-shaped, angles of the upper 1 

 ,.,, i * • i >Picus, Linn, 



mandible equal ; posterior outer toe longest. J 



2. Sub-typical group. 



{Bill rather depressed, angles of the upper man- "j 

 dible unequal ; two exterior toes of equal [Chrysoptilus, Sw. 

 length. ) 



3. Aberrant group. 

 f Bill depressed, culmen arched ; anterior fore toe ) 



bCANSORES. < . , >MALACOLOPHUS,Sw. 



[ longer than the hinder. J 



f Bill compressed, destitute of lateral angles, cul- I 



XENUIROSTRES. < . , fCoLAPTES, Sw. 



[ men cannated. J 



f Bill rounded, obsoletely angulated, culmen con- 1 



FlSSlROSTRES. < . , ., , >MeLANERPES, Sw. 



J vex ; wings lengthened. J 



These groups, independent of all peculiarities relating to structure, pre- 

 sent us with some curious facts in regard to geographic distribution. The 

 typical genus, as is almost universally the case, is spread over all parts of the 

 world : but as the continent of America, according to the profound observations 

 of Baron Humboldt, is that which above all others abounds in lofty and almost 

 interminable forests, the peculiar habitations of this family, so do we find that 

 the pre-eminently typical Woodpeckers are almost exclusively found in the New 

 World. There is not, in fact, as we shall presently show, one species in Europe, 

 and we know but of two or three from the continent of India. The sub-typical 

 genus is distributed precisely on the same principle : the typical species are 

 American, and the sw^-typical are European. Malacolophus is restricted to the 

 tropical latitudes of both hemispheres ; but here again do we find the same 

 regularity of distribution. The pre-eminent are chiefly, if not exclusively, con- 

 fined to the Brazilian forests ; while all the sub-typical species we have yet seen 

 are peculiar to the tropical parts of the Asiatic continent and its islands. Colaptes 

 occurs only in the more temperate parts of America and Africa ; but the types 

 are exclusively American, while Melanerpes appears altogether confined to the 

 New World. — As nearly all the species subsequently described belong to the 

 typical group, we shall enter into some details of the Genus 



