ADVERTISEMENT 



The scientific publications of the National Museum include two 

 series, known, respectively, as Proceedings and Bulletin. 



The Proceedings, begun in 1878, is intended primarily as a medium 

 for the pubHcation of original papers, based on the collections of 

 the National Museum, that set forth newly acquired facts in biology, 

 anthropology, and geology, with descriptions of new forms and re- 

 visions of Umited groups. Copies of each paper, in pamphlet form, 

 are distributed as published to libraries and scientific organizations 

 and to specialists and others interested in the different subjects. 

 The dates at which these separate papers are pubUshed are recorded 

 in the table of contents of each of the volumes. 



The Bulletin, the first of which was issued in 1875, consists of a 

 series of separate publications comprising monographs of large zoo- 

 logical groups and other general systematic treatises (occasionally in 

 several volumes), faunal works, reports of expeditions, catalogues 

 of type-specimens, special collections, and other material of similar 

 nature. The majority of the volumes are octavo in size, but a 

 quarto size has been adopted in a few instances in which large plates 

 were regarded as indispensable. In the Bulletin series appear vol- 

 umes under the heading Contributions from the United States National 

 Herbarium ,11). octavo form, published by the National Museum since 

 1902, which contain papers relating to the botanical collections of 

 the Museum. 



The present work forms No. 139 of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washington, D. C, November 8, 1926. 



Ill 



