+Guira piririgua+, _Scl. et Salv. Nomencl._ p. 107; _Durnford, Ibis_, 1877, p. 185 (Buenos Ayres); _Gibson, Ibis_, 1880, p. 8 (Buenos Ayres); _White, P. Z. S._ 1882, p. 619 (Buenos Ayres); _Barrows, Auk_, 1884, p. 26 (Entrerios); _Withington, Ibis_, 1888, p. 468 (Lomas de Zamora). +Ptiloleptis guira+, _Burm. La-Plata Reise_, ii. p. 443. _Description._--Above dark brown, with white shaft-stripes; head brown; wings reddish brown, passing into blackish brown on the outer secondaries; rump white; tail white, at the base ochraceous, crossed by a very broad black band, except the two central feathers, which are uniform brown: beneath sordid white, throat and upper breast with long linear black shaft-stripes; bill and feet yellow: whole length 15·0 inches, wing 7·0, tail 8·0. _Female_ similar. _Hab._ Brazil, Paraguay, and Argentina. "_Piririgua_," the specific term adopted by naturalists for this bird, is, according to Azara, the vernacular name of the species in Paraguay. He says that in that country it is abundant, but scarce in the Plata district. No doubt it has greatly increased and extended its range southwards during the hundred years which have elapsed since his time, as it is now very common in Buenos Ayres, where its vernacular name is _Urraca_ (Magpie). In the last-named country it is not yet quite in harmony with its environment. Everywhere its habit is to feed exclusively on the ground, in spite of possessing feet formed for climbing; but its very scanty plumage, slow laborious flight, and long square tail, so unsuitable in cold boisterous weather, show that the species is a still unmodified intruder from the region of perpetual summer many degrees nearer to the equator. The Guira Cuckoo is about sixteen inches long, has red eyes and blue feet, and an orange-red beak. The crown of the head is deep rufous, and the loose hair-like feathers are lengthened into a pointed crest. The back and rump are white, the wings and other upper parts very dark fuscous, marked with white and pale brown. Under surface dull white, with hair-like black marks on the throat and breast. The tail is square, 9 to 10 inches long; the two middle feathers dark brown, the others three-coloured--yellow at the base, the middle portion dark glossy green, the ends white; and when the bird is flying the tail, spread out like a fan, forms a conspicuous and beautiful object.