1917.] Chapman, Distribution of BirdAife in Colombia. 173 



venience in classification, labeling them with a name to which we can no 

 more help attaching the attributes of an entity, than we can avoid think- 

 ing of political boundaries as physical facts. 



Two species, for example, may be ninety-five percent alike, and five 

 percent unlike, in their so-called generic characters. The five percent of 

 unlikeness ismade the bagis of a generic division, a new name is giv-en and 

 the ninety-five percent of resemblance is thereby effectually concealed by 

 the combined results of analysis and nomenclature. I will illustrate with 

 the following examples: 



The American Quails to which the name Bob-white is commonly applied, 

 are By most authors placed in two genera, Colinus (or its nomenclSitural 

 equivalent Ortyx) and Ewpsychortyx. The 'generic' differences between 

 Colinus virginianus of the United States and Ewpsychortyx cristatus of 

 northern South America, structurally as well as geographically the most 

 widely separated species of the group, are found in the feathers of the head 

 and wings; ' Eupsychortyx' having the central crown-feathers elongated and 

 forming a well-defined crest, while the first (outer) primary is slightly 

 shorter than the eighth, rather than longer, as in Colinus. There is also a 

 well-marked difference in pattern of coloration, though both are obviously 

 quails. 



Current standards in ornithology would accept these differences as of 

 generic value, and if the two species mentioned were the only ones concerned, 

 the appropriateness of the generic distinctions mentioned would not be 

 questioned. But in Central America, from Yucatan to Costa Rica, or in 

 other words, from the southern limit of the range of true Colinus in Guate- 

 mala to the northern limit of the range of Eupsychortyx in western Panama, 

 there are found several species in which a crest is evident, in which the 

 wing-formula is sometimes that of the northern bird, at others that of the 

 southern, and which also approach the type of coloration shown by the 

 South American species. 



In short, so far as the characters mentioned are concerned, these Central 

 American species are intermediate or connecting forms. Practical evidence 

 of the truth of this statement may be found in their treatment by various 

 recent authorities, some of whom refer them to one 'genus' some to the 

 other. In spite of their superficial unlikeness, it is apparent, therefore, that 

 a line generically separating North American Bob-whites from South 

 American Bob-whites cannot be drawn, and hence it follows that' a nomen- 

 clature which recognizes generic distinction between them, conceals the 

 biologically significant fact of their group relationship. 



Evidence of the closeness of this relationship not found in the birds' 

 skins is supplied by their notes. The calls of all the species have not as 



