PREFACE V 



Comparative Zoology, Cambridge; National Museum of Canada, 

 Ottawa; Royal Ontario Museum of Zoology, Toronto; Museum of 

 Verterbrate Zoology, Berkeley; University of Michigan Museum, Ann 

 Arbor; Cornell University Museum, Ithaca; California Academy of 

 Sciences, San Francisco; Dickey Collection, University of California at 

 Los Angeles; Princeton University Museum; U. S. Fish and Wildlife 

 Service, Washington, D. C; Museum of Birds and Mammals, Uni- 

 versity of Kansas, Lawrence; British Museum (Natural History), 

 London; Museum d'llistoire Naturelle, Paris; Naturhistorisches 

 Museum, Vienna; Natural History Museum, Leyden; the collections 

 of Robert T. Moore, Pasadena, and the late J. H. Fleming, Toronto. 

 The total number of specimens thereby made available for study 

 in the present connection is hard to estimate but runs into many 

 thousands. 



As in Part X, the author has made extensive use of the manuscript 

 notes left by the late Robert Ridgway. His notes covered the diag- 

 noses of genera and higher groups and partial synonymies for many of 

 the species and subspecies. Wherever possible his manuscript has 

 been included with a mhiimum of change (other than addition to 

 synonymies) permitted by more recent data. However, unUke the 

 procedure followed in Parts IX and X the present author has not 

 felt constrained to keep the work as largely Ridgway's as possible and 

 has deleted some of his accounts of genera no longer considered valid 

 and has attempted to bring the whole account more in Une with cm*- 

 rent taxonomic opinion. Where any of Ridgw^ay's manuscript has 

 been incorporated it has been thoroughly studied with the specimens 

 and the hterature; nothing has been accepted merely because it was 

 already written. As in the previous two parts of this series the 

 author has felt himself responsible for the entire contents and has not 

 considered himseK as an editor of an unpublished work. 



A change in the form of citation in the synonymy of the birds is 

 instituted in this volume. In the earUer volumes by Ridgway, and 

 in the last two by the present author, in which Ridgway's system was 

 followed, care was taken to distinguish between references in which the 

 scientific name was completely spelled out and those in which parts 

 of it, such as the generic or the specific name (or both), were abbre- 

 viated or even left out; also distinction was made between diphthongs 

 and separate vowels. Beginning with the present part these distinc- 

 tions have been ignored, as the old method serves no real purpose. 

 Tliis is particularly true now that the literature is so very much more 

 extensive than it was when the series was started, and to continue 

 with the old system would merely add to the bulk and the expense of 

 producing this volume. 



