100 CICONIIFORMES CHAP. 
nineteen secondaries; the tail of twelve rectrices is usually short and 
even, or slightly rounded, but may be long, as in Comatibis, Geron- 
ticus, Cercibis, and Theristicus; 1n the last two of which it is cuneate. 
The furcula is U-shaped, the tongue rudimentary, the nostrils are 
pervious, an aftershaft is present, but there are no powder-down 
patches or syringeal muscles. Platalea leucorodia has the trachea 
convoluted like a figure of 8 in old birds. Adults and nestlings 
are uniformly downy, the latter varying from black with a white 
band over the crown in Plegadis to white in Platalea. 
Sub-fam. 1. Jbidinae.—Ibises are shy birds, which inhabit 
not only marshy spots and wooded country, but also the driest of 
plains and rocky gorges, being found both in pairs and in flocks. 
The flight is tolerably high and rapid, with extended neck and legs, 
most species habitually sailing or circhng aloft, though Plegadis 
rises with a whirr and skims along at no great elevation. On the 
ground the gait is graceful, and swimming is certainly practised 
at times, nor are perching or roosting on trees or reeds uncommon 
habits. The usual note is loud and harsh, lbis melanocephala 
being said to have a booming call’ and Jnocotis a melancholy 
scream”; the -food consists chietly of aquatic insects, molluscs, 
crustaceans, and worms; but small fish, lzards, newts, frogs, grass- 
hoppers, and beetles form part of the diet ; Geronticus, which does 
not despise carrion, acts as a scavenger. Most Ibises wade in 
pursuit of prey, whether in fresh or salt water, moving the bill to 
and fro, and probing the subjacent mud. Some species breed apart, 
others in colonies; the nest being placed on trees or low bushes, 
and more rarely among reeds, or, as in Geronticus and Comatibis, 
in holes in cliffs or on ledges. The structure is not remarkably 
large, and is composed of sticks or stems of plants, with or with- 
out a lining of herbage, straw, or roots ; the eggs, from two to four 
in number, being deep green-blue in Plegadis, pale blue in Grapto- 
cephalus, similar or darker in Jnocotis, olive-green in Hagedashia, 
and greenish-white in Jb7s and Hudocimus, or even brownish in the 
last-named. In all except the first two there are generally reddish 
or brownish markings. Incubation lasts about three weeks. 
Eudocimus ruber and £. albus, the Searlet and White Ibises of 
tropical America, are respectively coloured as the names import, the 
tips of the longer primaries and of the bill being black, while the 
1 Hume, ed. Oates, Nests and Eygs of Indian Birds, iii. 1890, p. 227. 
2 Jerdon, Birds of India, ti. Calcutta, 1877, p. 770 
