TREE-FROG, or TREE-TOAD. A frog of the family Hylidte, connecting the toads with the typical frogs, and of prevailingly arboreal habits. Tree-frogs have teeth on the upper jaw and vo mers, and in some genera elsewhere in the mouth. The toes are invariably claw-shaped and swollen at the base; and each carries at the tip a flat tened, adhesive cushion, whose sticky secretion greatly aids the animal in clinging to smooth sur faces. Most of them are of small size, more ele gant in form than the Irlie frogs, of brighter col ors and more active habits. They feed on insects, which they pursue on the branches and among the leaves of trees or shrubs. All have loud, piping notes, and are remarkable for their power of changing their colors to simulate the tint of the resting-place. (See MErAcuaosis.) They are also remarkable for the great variety in their meth ods of placing their spawn, and the character of their metamorphoses, which are severally de scribed under CR1CKET-FROG, FERREIRO, MAR SUPIAL FROG, etc. The principal genus is Ilyla, which contains about 150 species scattered all over the warmer forested parts of the world, but especially numerous in tropical America. The
type is Hyla ar•borea, common throughout all Central and Southern Europe and Asia. Of the North American species the most familiar is Ilyla versicolor, which is a green, gray, or brown warty frog, whose clear, loudly trilled rattle is an almost daily evening sound. One of the first notes heard in the spring in the Eastern United States is the piping of Hyla Pickeringii, smaller, more yellowish species, often called 'the peeper.' The cricket-frog (q.v.) is another nu merous species. Various others inhabit the South ern States. Many species of the West Indies and South America carry their eggs about on the back of the females, glued to or sunken into the skin, as is notably the case with Hyla Goeldii. Notable cases are described in the Proceedings of the Zoological Society of Loudon for 1895. Aus tralia possesses several species of great interest, especially the familiar Hyla Orrulea, whose cry is a sharp crackling bark. The whole group is one of extraordinary variety and interest.
Consult authorities cited under FROG. See Colored Plate accompanying article TOADS.