_Description._--White above and beneath; adult with a long occipital crest of decomposed feathers and dorsal plumes lengthened; lores and toes yellow; bill black, yellow at base; legs black, behind yellowish at the lower part: whole length 24·0 inches, wing 9·5, tail 4·0. _Female_ similar. _Hab._ North and South America. The Snowy Egret is common on the pampas, and throughout all the warm portions of North and South America; but does not range so far south as _Ardea egretta_. It is a very pretty bird in its dazzling white plumage, and is more active and social in its habits than most Herons, being usually seen in small flocks, and often associates with Ibises and other aquatic species. An account of its breeding-habits has already been given. 318. ARDEA CÆRULEA, Linn. (BLUE HERON.) +Ardea cærulea+, _Burm. La-Plata Reise_, ii. p. 509. +Florida cærulea+, _Baird, Brew., et Ridgw. Water-B. N. A._ i. p. 43. _Description._--Dark bluish plumbeous; head and neck purplish chestnut; bill blue, blackish at the end; feet black: whole length 20·0 inches, wing 9·0, tail 3·6. _Female_ similar. _Hab._ North and South America. This well-known North-American Heron extends far to the south. Natterer obtained examples at several places in the province of Sao Paolo, Brazil. Dr. Burmeister tells us that he met with it on the Rio Negro, and also near Mercedes in the Argentine Republic. 319. ARDEA SIBILATRIX, Temm. (WHISTLING HERON.) +Ardea sibilatrix+, _Temm. Pl. Col._ 271; _Scl. et Salv. Nomencl._ p. 125; _iid. P. Z. S._ 1869, p. 634 (Buenos Ayres); _White, P. Z. S._ 1882, p. 624 (Salta); _Barrows, Auk_, 1884, p. 271 (Entrerios). _Description._--Above grey; cap, occipital crest, and wing-feathers greyish black; large patch behind the eye rufous; upper wing-coverts rufous, striped with grey: beneath white, breast tinged with yellowish; bill reddish, tip black; feet black: whole length 22·0 inches, wing 11·5, tail 4·5, tarsus 3·4. _Female_ similar. _Hab._ South America. This is a beautiful bird, with plumage as soft as down to the touch. Its colours are clear blue-grey and pale yellow, the under surface being nearly white. In some specimens that I have obtained the rump and tail-coverts had a pure primrose hue. There is a chestnut mark on the side of the head; the eye is white, and the legs dark green in life. Azara named this Heron "_Flauta del Sol_" (flute of the sun), a translation of the Indian term _Curahí-remimbí_, derived from the popular belief that its whistling notes, which have a melodious and melancholy sound, prophesy changes in the weather.