_Definition._--Medium to large tree frogs having: (1) broad, well ossified skull (consisting of a minimum amount of cartilage and/or secondarily ossified cartilage), (2) no dermal co-ossification, (3) quadratojugal and internasal septum present, (4) large ethmoid, (5) _M. depressor mandibulae_ consisting of two parts, one arising from dorsal fascia and other from posterior arm of squamosal, (6) divided _M. adductor mandibulae_, (7) paired subgular vocal sacs in males, (8) no dermal appendages, (9) pupil horizontally elliptical (10) small amounts of amines and other active substances in skin, (11) chromosome number of N = 12 and 2N = 24, (12) breeding call consisting of poorly modulated, explosive notes, and (13) 2/3 tooth-rows in tadpoles. _Composition of genus._--As defined here the genus _Smilisca_ contains six recognizable species. An alphabetical list of the specific and subspecific names that we consider to be applicable to species of _Smilisca_ recognized herein is given below. Names proposed Valid names _Hyla baudini_ Dumeril and Bibron, 1841 = _S. baudini_ _Hyla baudini dolomedes_ Barbour, 1923 = _S. phaeota_ _Hyla beltrani_ Taylor, 1942 = _S. baudini_ _Hyla gabbi_ Cope, 1876 = _S. sordida_ _Hyla labialis_ Peters, 1863 = _S. phaeota_ _Hyla manisorum_ Taylor, 1954 = _S. baudini_ _Hyla muricolor_ Cope, 1862 = _S. baudini_ _Hyla nigripes_ Cope, 1876 = _S. sordida_ _Hyla pansosana_ Brocchi, 1877 = _S. baudini_ _Hyla phaeota_ Cope, 1862 = _S. phaeota_ _Hyla phaeota cyanosticta_ Smith, 1953 = _S. cyanosticta_ _Hyla puma_ Cope, 1885 = _S. puma_ _Hyla salvini_ Boulenger, 1882 = _S. sordida_ _Hyla sordida_ Peters, 1863 = _S. sordida_ _Hyla vanvlietii_ Baird, 1854 = _S. baudini_ _Hyla vociferans_ Baird, 1859 = _S. baudini_ _Hyla wellmanorum_ Taylor, 1952 = _S. puma_ _Distribution of genus._--Most of lowlands of Mexico and Central America, in some places to elevations of nearly 2000 meters, southward from southern Sonora and Rio Grande Embayment of Texas, including such continental islands as Isla Cozumel, Mexico, and Isla Popa and Isla Cebaco, Panama, to northern South America, where known from Caribbean coastal regions and valleys of Rio Cauca and Rio Magdalena in Colombia, and Pacific slopes of Colombia and northern Ecuador. Key to Adults 1. Larger frogs ([M] to 76 mm., [F] to 90 mm.) having broad flat heads and a dark brown or black postorbital mark encompassing tympanum 2 Smaller frogs ([M] to 45 mm., [F] to 64 mm.) having narrower heads and lacking a dark brown or black postorbital mark encompassing tympanum 4