The orders under which the birds of the world are arranged in the scheme of classification adopted by Wallace in his great work on the geographical distribution of animals are as follows: CLASS--AVES ORDERS. EXAMPLES. 1. Passeres Includes the greater number of the smaller birds, such as kingbirds, flycatchers, larks, jays, crows, blackbirds, finches, sparrows, warblers, chickadees, swallows, thrushes, etc., numbering in North America some 328 species and many subspecies. 2. Picariae Woodpeckers, cuckoos, toucans, kingfishers, swifts, goat-suckers, humming-birds, etc. 3. Psittaci Parrots only. 4. Columbae Pigeons and the dodo. 5. Gallinae Grouse, pheasants, quail, jungle-fowl, turkeys, guinea-fowl, etc. 6. Opisthocomi The hoazin of Guiana and Brazil only. 7. Accipitres Eagles, owls, vultures, hawks, buzzards, falcons, etc. 8. Grallae Rails, snipes, plovers, cranes, herons, storks, flamingoes, etc. 9. Anseres Ducks, geese, gulls, petrels, pelicans, penguins, loons, auks, etc. 10. Struthiones Ostrich, rhea, cassowaries, emeus, apteryx. Of these ten orders, all but two are abundantly represented in North America. The missing orders include the ostrich-like birds, of which the only species in the New World is the rhea, of the southern portion of South America, and the peculiar hoazin, represented by a single species found in Guiana and Brazil. The eight orders under which the birds of North America have been arranged (other classifications, however, have been adopted by various naturalists) have again been subdivided into families, genera, species, etc. According to Wallace's summary, the 8 orders referred to contain 124 families, of which 75 are not represented in North America to the north of the lowlands of Mexico, while 47 families are present. Of these 47 families, 25 are essentially of world-wide distribution, and only 1, containing a single species, a small wren-like bird of the genus _Chamaea_, found in California, is peculiar to the fauna of the continent. As the North American continent under the arrangement adopted for the series of books of which the one in hand forms a part, is considered as including the West Indies, Mexico, and Central America, the above summary does not represent its entire bird fauna, but presents, perhaps, the best general idea of it that is at present attainable. To include the birds of the tropical portion of the continent would add greatly to the number of species, but I believe not materially to the number of families and orders, as given above.