1914] Beebe: Revieiv of the Genus, Gennseus. 305 



Pheasant and the Black-shouldered Peafowl. I am now of the 

 opinion that both forms of variation have been operative in 

 the origin of wild forms and that the difference between them 

 is pronounced if not profound. As an example of continuous 

 variation I would cite the entire genus Phasianus (as I have 

 recently restricted that groups ) . The supergenus Euplocamus 

 well illustrates in its generic divisions what seem to be salta- 

 tions. 



The moment one attempts to define genera and subgenera 

 in such a homogeneous group of organisms as the pheasants, 

 one becomes aware of the personal equation. In the division 

 into subfamilies I have sought to eliminate this by making use 

 of the only consistent character which I could discover, namely, 

 the sequence of moult of the tail feathers. With the impos- 

 sibility of appeal to osteological or other fundamental charac- 

 ters, we are compelled to fall back upon purely superficial 

 distinctions. Where the resemblances are as numerous as the 

 differences, and yet when convenience in discussing the various 

 groups demands some taxonomic isolation, however artificial, 

 one again instinctively begins a search for something which 

 will help to eliminate the personal element. This personal equa- 

 tion is in very truth affected by H and O and E and S, and its 

 variation is enormous. So it behooves one to attempt to base 

 one's taxonomic belief on something more stable and more 

 acceptable to foreign fellow ornithologists, than the mere ci^edo 

 derived from the multitudinous mental forces, both true and 

 erroneous, resulting from American education and American 

 environment. 



Looking over the groups of pheasants, in number about a 

 score, it seems to me that there is a criterion which may be 

 adopted for differentiation into genera. Like the sequence of 

 tail moult it is a character which must be consistently applied 

 throughout the family, and, also like that character, it is 

 abstractly doubtless of no value, at least in many other families 

 of birds. But if it helps in deciding a few cases which seem 

 so evenly balanced that their position might rest upon the turn 

 of a coin, it will be worth while. This factor which throughout 

 my studies has gained in cumulative significance, is that, no tivo 

 species of any one genus occupy the same geographic area. This 



1 Preliminary Pheasant Studies, Zoologica, I. No. 15, 1914, pp. 283-284. 



