Sub-fam. 4. _Odontophorinae_,[164]–The "American Partridges," are Quail-like birds, rarely attaining the size of a Red Grouse, and readily distinguished from their kin by the doubly-toothed mandible and the lack of spurs. The sexes are alike, if not otherwise stated. Of some four species of _Dendrortyx_, ranging from South Mexico to Costa Rica, _D. macrurus_, of the former country, has a black head and throat, with a long white streak above and below each eye, and a rufous tip to the short, full occipital crest. The neck and back are chestnut and grey; the rump, wings, and tail are browner with black mottlings; the breast is greyish with rufous streaks. The bill, feet, and naked orbits are coral-red. _Callipepla squamata_, of the South-Western United States and Mexico, has a grey-brown head, with white-tipped crest and buff throat; the wings, rump, and tail are brownish-grey with white inner margins to some of the scapulars and secondaries; the mid-breast and belly are fawn-coloured. The remaining plumage is grey, with black margins to the feathers which cause a scaly appearance, and shews dusky triangular spots beneath. _Oreortyx pictus_ of the Western United States possesses two very long black occipital plumes; olive-brown upper parts with white edges to the scapulars and outer secondaries; slaty head, neck, {231}and lower surface, with chestnut throat and abdomen, of which the former is laterally margined with white; a white band from the chin to the lores; and chestnut flanks, barred with black and white. _Lophortyx californicus_, of the same countries, has the head and crest of two club-shaped feathers black, a yellow forehead, olive-grey upper parts, a black throat outlined with white, buff mid-breast, and chestnut belly, each feather of the last two being edged with black. A white band connects the eyes and continues behind them, while white streaks grace the sides and flanks. The female lacks the black and white pattern on the head, and has whitish lower parts with yellow-brown throat. Two other species extend the range to Mexico, _Philortyx fasciatus_ of South Mexico has an olive-brown upper surface, washed with rufous on the crown and the greyer neck and mantle, and barred or blotched with black and buff on the lower back, wings, and tail; the blackish crest is tipped with red; the throat and lower parts are white, with a few median spots and pronounced black bars on the chest, sides, and flanks, where the feathers have rusty margins. _Eupsychortyx cristatus_ of Curaçao and Aruba has half a dozen congeners, ranging through Central and northern South America. It has a buff crest, crown, and throat; black and white nape and cheeks; reddish-grey upper parts mottled and blotched with black and buff; and rufous lower surface, barred with black, and spotted on the chest, sides, and flanks with white. In the female the black on the head is replaced by buff. _Ortyx virginianus_ of the Eastern United States