PEEFACE. 



The great size to which the Tenth Yolume of the ' Catalogue of 

 Birds in the British Museum ' has grown has been caused, in great 

 measure, by the pains which the author has taken in tracing and de- 

 scribing in detail the seasonal changes of plumage of many of the 

 Birds — which could not be attempted without long series of 

 examples marked with the locality and exact date of capture. 



However, if with the present volume, at least as regards the 

 South- American Avifauna, a greater degree of completeness has 

 been attained than was possible in the preceding portions of the 

 work, it is chiefly due to the recent transference to the British 

 Museum of the two most important collections of South-American 

 Birds that have been brought together in modern times. 



The first is the celebrated collection of American Passeres, formed 

 by P. L. Sclater, Esq., F.R.S., in the course of the last thirty years. 

 It contains most of the material on which the majority of the 

 publications of this Ornithologist were based, and is, perhaps, the 

 first collection of its kind that was made, at least in this country, 

 with a clear understanding of the great importance of well ascer- 

 tained localities. 



For the second the Trustees are indebted to the generosity of 

 0. Salvin, Esq., F.R.S., and F. D. Godman, Esq., F.E.S. Formed 

 with the same care as the Sclater Collection, it surpasses this 

 latter as regards the number of specimens, illustrating more fully 



