Localities: Guatemala (SCL. Ibis I, 219); Veragua (SALV. P. Z. S. 1867, 158); Sta. Cruz (NEWTON, Ibis, I, 63); Trinidad (TAYLOR, Ibis, 1864, 80); Bahamas (BRYANT, Pr. Bost. Soc. 1859, VII); Cuba (CAB. Journ. II, lxxxiii); (GUNDL. Repert. 1865, 225); Jamaica, (GOSSE, B. Jam. 16; MARCH, Pr. Ac. N. S. 1863, 304, et Mus. S. I.); Tierra del Fuego (SHARPE, Ann. & Mag. N. H.; “_F. cassini_, SHARPE”). The young plumage above described corresponds exactly with that of young _peregrinus_ from Europe, a comparison of the specimen above described with one of the same age from Germany (54,064, Schlüter Col.) showing no differences that can be expressed. Many American specimens in this plumage (as 19,397, Fort Simpson) show a wash of whitish over the forehead and anterior part of the crown; having before us but the one specimen, we cannot say whether or not this is ever seen in the European bird. Specimens more advanced in season—perhaps in second year—are colored as follows: The black above is more brownish, the feathers margined with pale brown,—these margins broader, and approaching to white, on the upper tail-coverts; the tail shows the ochraceous bars only on inner webs. The supraoral stripe of the youngest plumage is also quite apparent. A still younger one from the same locality (No. 37,397) has the upper plumage similar to the last, the pale edges to the feathers, however, more distinct; tail with conspicuous spots. White beneath clearer, and invading the dusky of the head above as far back as the middle of the crown; the supraoral stripe is distinct, scarcely interrupted across the nape. In the adult plumage the principal variation is in the extent and disposition of the bars beneath. In most individuals they are regularly transverse only laterally and posteriorly, those on the belly being somewhat broken into more irregular cordate spots, though always transverse; in no American specimen, however, are they as continuously transverse as in a male (No. 18,804) from Europe, which, however, in this respect, we think, forms an exception to most European examples, at least to those in the Smithsonian Collection. All variations in the form, thickness, and continuity of the markings below, and in the distinctness of the bars above, are individual. Very old males (as 49,790, Fort Yukon; 27,188, Moose Factory (type of Elliott’s figure of _F. peregrinus_, in Birds of America); and 42,997, Spanishtown, Jamaica) lack almost entirely the reddish tinge beneath, and have the lateral and posterior portions strongly tinged with blue; the latter feature is especially noticeable in the specimen from Jamaica, in which also the bars are almost utterly wanting medially. Immature birds from this island also lack to a great degree the ochraceous tinge, leaving the whitish everywhere purer.