The LAUGHING HAWK (_Herpetotheres cachinnans_) is a South American bird, to which we have assigned the first place, inasmuch as in some respects it resembles the Falcons; the name it bears has been given to it on account of the very peculiar sound of its loud and resonant voice. Its distinguishing characteristics are its comparatively large head, which is profusely covered with feathers, and the robust development of the hinder parts of its body. The wings when closed reach to the middle of the tail, their primaries are narrow and pointed, the third and fourth quills being longer than the rest; the tail is long, the exterior feathers somewhat shortened; the tarsi are of moderate height and strength, the toes small, and the claws remarkably short and thick; the beak is short, much compressed at its sides, and terminates in a short hook; the lower mandible is shallow, and bifurcated at its tip; the region of the eye is bare, and the body covered with long-pointed and strong-shafted feathers. In size the Laughing Hawk resembles its European congeners; the plumage is pale yellow from the top of the head to the nape, each feather having a black shaft; the bridles, nape, and cheeks are black, the mantle brown, the feathers being bordered with a lighter shade; the entire lower portion of the body and a stripe upon the neck are white, which changes into red upon the breast and legs; the upper part of the tail is black, its under portion whitish yellow, tipped with white and ornamented with six or seven grey stripes; the inner web of the brown quills which form the wings is shaded from reddish yellow to white, and edged with a delicate irregular brown line; the eye is reddish yellow, the beak black, the cere and legs are yellow. THE DOUBLE-TOOTHED HAWK. The DOUBLE-TOOTHED HAWK (_Harpagus bidentatus_) resembles the Falcons in its general form, but is recognisable by its comparatively small head, long broad tail, and short wings. The beak is very peculiar in its construction, the upper portion being excised immediately behind the hook at its tip, and the lower mandible, which terminates abruptly, has near its extremity two sharp teeth at each side; the third quill of the wings is longer than the rest, the tarsi are short, and of the same length as the toes. This bird, of which there are two species, is only found in South America.