The FLOWER BIRDS (_Certhiola_) constitute a small group of South American species, remarkable for the great beauty of their plumage. All possess a slender body, moderate-sized wing, containing nine primaries (of which the second, third, and fourth are the longest), and a somewhat soft-feathered tail, of medium length. The beak is also of moderate size, much arched at its base, and curved slightly inwards at its margins. The tongue is long, divided, and thread-like at its tip, but not protrusible; the foot is short and powerful. The sexes are readily distinguishable by the diversity of their coloration, the plumage of the male being blue, and that of the female usually green. All the members of this group closely resemble our singing birds in their habits and mode of life; they subsist upon insects, seeds, corn, and berries, in pursuit of which they hop from branch to branch, with ever restless activity. According to the Prince von Wied, they regard fruit of various kinds, particularly oranges, with especial favour, and, when these are ripe, constantly venture into the gardens, even close to dwelling-houses, with all the fearlessness of the Domestic Sparrow; at other seasons they prefer to keep within the shelter of well-wooded thickets. Their song, we believe, consists of but a single note. * * * * * The BLUE BIRDS (_Cæreba_) are at once recognisable by their long, thin beak, which is compressed at its sides, and slightly notched near its very sharp tip; the wing is long and pointed, its second and third quills, which are of equal size, exceeding the rest in length. The moderate-sized tail is straight at its extremity; the legs are weak, and the tongue, which is tolerably long, composed of two lobes, terminating in fringed margins. THE SAI, OR BLUE CAEREBA. The SAI, or BLUE CAEREBA (_Cæreba cyanea_). The prevailing colour of this beautiful species is a brilliant light blue, shading towards the top of the head into resplendent blueish green; the upper part of the back, wings, and tail, as well as a stripe surrounding the eye, are black, and the inner margins of the wings yellow. The eye is greyish brown, the beak and foot bright orange-red. The plumage of the female is siskin-green on the upper parts of the body, and pale green beneath; the throat is whitish. The length of this species is four inches and two-thirds, the wing measures two inches and a quarter, and the tail one inch and a quarter. [Illustration: THE SAI, OR BLUE CAEREBA (_Cæreba cyanea_).]