Sub-fam. 4. _Sterninae._–The Terns may be commenced with the snow-white _Gygis candida_, which ranges from the islands east of Brazil to Ascension, St. Helena, Madagascar and its vicinity, the Indian Ocean, the Malay countries, Australia, the Ladrones, the Sandwich Islands and Polynesia generally. The form and habits have been already noticed (pp. 301, 303). The smaller slender-billed _G. microrhyncha_ seems to be peculiar to the Marquesas. _Anous stolidus_, termed with its congeners the "Noddies" from their stolid indifference at times to man, chiefly frequents tropical and sub-tropical regions, and has occurred once in Ireland. It is {311}sooty-brown, with whitish forehead, grey head, black bill and lores, and reddish-brown feet; _A. galapagensis_ of the Galápagos being entirely sooty-black above. _A. (Micranous) leucocapillus_, with a weaker bill and a white crown, has a somewhat more restricted range; _A. (M.) tenuirostris_, with grey lores, ranges from the neighbourhood of Madagascar to Australia; _A. (M.) hawaiiensis_, with lighter upper parts, occurs around the Sandwich Islands. These species make a large flat nest of twigs, leaves, grass, and sea-weed, on trees, bushes, or even on the ground, laying one buffish-white egg with scattered red-brown markings. Several pairs often use one tree. _A. (Procelsterna) cinereus_, extending from Australia to Chili, and _A. (P.) caeruleus_ of Central Polynesia, are nearly grey above, but the former is white beneath. The egg is ordinarily deposited with little or no nest on a bare rock or on sand. In all the rest of the Sub-family the tail is forked instead of graduated, though less markedly in _Naenia inca_ of Peru and Chili, which is leaden-grey, with curling white plumes below the eye, red bill and feet. The genus _Sterna_ contains the more typical Terns or Sea-Swallows, of which the coloration–unless subsequently mentioned–is grey above, and white or lighter grey beneath and on the tail. _S. trudeaui_ of Brazil, Argentina, and Chili, which strays to the United States, and _S. melanauchen_, ranging from the Amirante and Seychelles Islands to the Liu Kiu group and Polynesia, are the only two species with the crown white in place of black in the breeding season; the former bird has a black streak through the eye, the latter a band from the lores to the nape.