Ridgway's 'The Birds of North and Middle America,' Part IV The Birds of North and Middle American: A Descriptive Catalogue of the Higher Groups, Genera, Species, and Subspecies of Birds Known to Occur in North America, from the Arctic Lands to the Isthmus of Panama, the West Indies and Other Islands of the Caribbean Sea, and the Galapagos Archipelago. Part IV Robert Ridgway Some Observations concerning the American Families of Oligomyodian Passeres Robert Ridgway