VI PREFACE, 
institutions as have already been named in previous volumes; also 
to Mr. C. H. Lankester, of Cachi, Costa Rica, who kindly placed the 
Tracheophones of his fine collection of Costa Rican birds at the au- 
thor’s service. 
To Sefior Don José C. Zeledén, of San José, Costa Rica, the author 
is specially indebted for most generous help, at considerable expense 
to himself, in making a very fine collection of the birds of that country, 
which proved of incalculable value in the preparation of this work. 
Dr. C. W. Richmond, Assistant Curator, and Mr. J. H. Riley, Aid, 
of the Division of Birds, U.S. National Museum, have rendered invalu- 
able assistance; Dr. Richmond through his special knowledge of 
ornithological bibliography and his extremely useful and very com- 
plete card catalogue of generic and specific names, made at ‘‘first 
hand,” or directly from the publication in which each name was first 
published, as well as by carefully scanning the proof sheets with par- 
ticular reference to correctness of citations in the synonymy; Mr, 
Riley, by copying references from various publications, but espe- 
cially through having performed the tedious task of measuring several 
thousands of specimens." 
There has been some criticism of the present work on the ground 
that certain books, local lists, and other publications have not been 
cited in thesynonymies. The omission of these is very much regretted 
by the author, who in explanation, if not justification, would state 
that it has been quite impossible for him to cover the whole field; 
that the literature of ornithology is so vast, and increasing so rapidly, 
that to bring the bibliography and synonymy of all the species up 
to date and keep it so would require all the time that any one indi- 
vidual could possibly give to it; and that since much the greater 
part of this labor (which has justly been termed ‘‘the drudgery of 
ornithology’) has been done by the author himself, very largely in 
his own time (which means during hours which should have been 
1 The number of specimens examined during the preparation of this volume is as 
follows: 
Collection of the U. 8. National Museum. .........2...22.-20..-20000 2000 ee 4, 846 
Collection of the Biological Survey. .....-.-..--..--- ene ee eae 1,118 
Collection of the American Museum of Natural History. ...............-...- 2, 255 
Collection of the Carnegie Museum.............22-2.--02220202 022 e eee eee ee 1, 358 
Collection of the Field Museum of Natural History. ...-.................2.. 478 
Collection of the Academy of Natural Sciences, Philadelphia............... 170 
Collection of the Boston Society of Natural History...............2....... 6 
Collection of the Museum of Comparative Zoology.....-.-..........2.2.2--- 2, 097 
Collection of the Museo Nacion4l, Costa Rica... 2.2... 2. eee eee cece eee ee 66 
Collection of the Museum of Vertebrate Zoology, University of California. ... 4 
Collection of A. E. and O. Bangs, Boston... ........2 0.00. cece eee e eee eee 1, 877 
Collection of C. H. Lankester, Cachi, Costa Rica 
