The present volume contains an account of the Passeres of the Argentine Republic, which, as at present known, number some 229 species. The second volume, which it is hoped will be ready in the course of next year, will be devoted to the history of the remaining Orders of Birds, and will also contain the Introduction and Index, and complete the work.

All the personal observations recorded in these pages are due to Mr. Hudson, while I am responsible for the arrangement, nomenclature, and scientific portions of the work.

I have to acknowledge with many thanks a donation of £40 from the Royal Society, which has enabled Mr. Hudson to devote a portion of his time to the compilation of his interesting notes.