ADVERTISEMENT 



The scientific publications of the National Museum include two 

 series, known, respectively, as Proceedings and Bulletin. 



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

 medium for the publication of original papers, based on the collec- 

 tions of the National Museum, that set forth newly acquired facts in 

 biology, anthropology, and geology, with descriptions of new forms 

 and revisions of limited groups. Copies of each paper, in pamphlet 

 form, are distributed as published to libraries and scientific organi- 

 zations and to specialists and others interested in the different sub- 

 jects. The dates at which these separate papers are published are 

 recorded in the table of contents of each of the volumes. 



The series of Bulletins., the first of which was issued in 1875, con- 

 tains separate publications comprising monographs of large zoologi- 

 cal groups and other general systematic treatises (occasionally in 

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

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

 ilar 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 Bidletin series appear vol- 

 umes under the heading Contributions from the United States Na- 

 tioTial Herhariumi, 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. 158 of the Bulletin series. 



Alexander Wetmore, 

 Assistant Secretary., Smithsonian Institution. 



Washington, D. C, August 16, 1932. 



IV 



