sofc.n^ 



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 publication 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 revi- 

 sions of limited 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 difterent subjects. The 

 dates at which these separate papers are published are recorded in 

 the table of contents of each of the volumes. 



The Bulletins, the first of which was issued in 1875, consist 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 m 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 

 Herharium, in 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. 151, of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary, Smithsonian Institution. 



Washington, D. C, November 26, 1929. 



