VI PREFACE. 



Stejneger assisted me very materially by his criticism and 

 suggestions, he having devoted more attention to this 

 subject than any other American ornithologist. Dr. 

 Elliott Coues furnished me with several useful terms 

 (some of them new), as well as many suggestions which 

 have been of value. Mr. F. C. Test of Washington, Mr. 

 Witmer Stone of the Philadelphia Academy of Sciences, 

 and Dr. J. A. Allen and Mr. Frank M. Chapman of the 

 American Museum of Natural History, have aided my 

 work, both by placing their collections at my disposal 

 and by furnishing me with valuable facts and sugges- 

 tions. Dr. Allen's important contributions to the sub- 

 ject here discussed have been of far more service than 

 the mere quotations indicate. To Mrs. Katharine Bran- 

 degee and Mr. Frank H. Vaslit I desire to return thanks 

 for their kind and painstaking revision of the proof, 

 also to Mr. Walter E. Bryant, who read the proof for 

 scientific terminology. 



BERKELEY, Gal., December 21, 1892. C. A. K. 



