The birds of this genus are remarkable for the enormous width of their mouths, which in some species exceeds that of the Swallow family, thus enabling them with ease to swallow the large berries of the _Melastomae_ and other tropical shrubs, on which they alone subsist; not on insects, as Cuvier asserts. Although in the construction of their bills they perfectly resemble the Swallows, their wings are not formed for long or rapid flight; and their feet are much stronger, and calculated for searching among branches for their food, in which situations I have frequently seen them. The term "_pedes ambulatorii_," or walking-feet, is applied too generally, and should be confined to the gallinaceous and Pigeon tribes. This genus was formed by Count Hoffmansegg, and the present is the smallest species known: our figure is of the male bird. Total length about five inches and a half. The bill from the angle to the tip measures seven lines; but from the nostrils only three lines and a half. The middle of the body, vent, and under tail-covers in the male are pure white; in the female yellowish, with a line of olive-green down the middle of each shaft; the quills, wing-covers, and tail-feathers are black, margined in the male with blue, and in the female with green: the tail is slightly forked. The nostrils round and bare; the base of the bill has a few weak setaceous hairs. The legs resemble the true Chatterers, having the outer toe rather longer than the inner, and attached to the base of the middle. This is a scarce bird, apparently not hitherto described; I met with it only three times in Bahia; but it appears more frequent in the southern provinces of Brazil, specimens having been sent me from Minas Geralis and Rio de Janeiro. * * * * * Pl. 22 [Illustration] TERIAS Elvina. * * * * * GENERIC CHARACTER. _Antennae breves, clava subtruncata, compressa. Palpi brevissimi curvati, vix ultra caput producti, ad linguam compressi, densis squamis imbricatis in totum tecti apice nudo. Abdomen elongatum, gracile, in maribus 6-articulatum, articulo ultimo duobus uncis incurvatis approximantibus; valvis latis, incrassatis, truncatis, aduncis. Alae utroque sexu similes; latae, obtusae, rotundatae, integerrimae._ Typus Genericus _Papilio Hecabe_. Linnaeus. Antennae short, the club somewhat truncate and compressed. Palpi very short, curved, hardly projecting beyond the head, closely compressed on the tongue, entirely covered with close imbricate scales, the tip naked. Body elongated, slender, in the male six-jointed, the last with two approximating incurved hooks; valves broad, thickened, truncate, and hooked. Wings in both sexes alike, broad, obtuse, rounded, very entire. Generic Type _Papilio Hecabe_. Linnaeus. * * * * * SPECIFIC CHARACTER.