530 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.42. 



from south of the United States; and the literature on the subject 

 consists of only notes and short papers, including no extended 

 monograph of the species. The series of specimens now at hand is 

 undoubtedly much greater than any that other investigators have 

 been able to bring together. With this advantage, the present writer 

 hopes to make at least some contribution to our knowledge of this 

 perplexing group, although, of course, he fully realizes that there is 

 much yet to learn. 



One of the by-products, so to speak, of this investigation has been 

 the necessary determination of the status of Butorides hrunescens 

 (Lembeye)* of Cuba, which occurs together with the form of Butorides 

 virescens inhabiting that island. This bird has often passed as 

 merely a color phase of Butorides virescens; at other times as a differ- 

 ent species : The writer's study indicates that without much doubt it 

 is a perfectly distinct species, further discussion of which has already 

 appeared in a separate paper.^ 



From a careful study of the present material, two conclusions 

 appear to be inevitable: First, that, without undue and useless 

 refinement, no subspecific subdivision is possible among the birds 

 inhabiting all of the eastern United States, eastern and central 

 Mexico, south to Guatemala and Honduras; and second, that, in the 

 West Indies, either we must recognize a large number of additional 

 forms, or merge all, includmg even Butorides virescens hahamensis, 

 with Butorides virescens virescens. To adopt the latter alternative, 

 however, would be to obscure all the evident and highly interesting, 

 though to some extent puzzling, geographical variations which these 

 West Indian birds exliibit. The writer has, therefore, adopted the 

 former course, as better representing the facts ; and this has resulted in 

 allotting a separate subspecies to each of the larger Lesser Antilles 

 south of Guadeloupe, with the single exception of St. Vincent. In 

 one or two cases where forms are separated by a vnde geographic 

 area and by intervening races, it has been thought better to recognize 

 by name slight average differences, rather than to refer such a bird 

 to a distant and isolated race, to which, although superficially very 

 similar, it could have no close phylogenetic relationship. This, of 

 course, is the same problem that one meets often in wide-ranging and 

 plastic groups, and which, it seems to the writer, would be in much 

 the best way solved by assigning a name to the isolated colony, if 

 there can be found any characters at all, however slight, to serve as 

 a basis. 



The geograpliical range of Butorides virescens, including its various 

 subspecies, extends from southeastern Canada tlirough the United 



1 Ardea brunescens Lembeye, Aves de la Isla de Cuba, 1850, p. 84, pi. 12. 

 » Oberholser, Proc. Biol. Soc. Wash., vol. 25, 1912, pp. 63-56. 



