_Distribution._--_Hyla microcephala microcephala_ inhabits coastal lowlands from the area of Golfo Dulce (apparently absent from the Osa Peninsula) in southeastern Costa Rica eastward in Panamá, including the Azuero Peninsula to northern Colombia and thence southward in the valleys of the Río Cauca and Río Magdalena in Colombia (Fig. 1). Except for the central area of the Canal Zone the subspecies is unknown from the Caribbean drainage in Central America, but in Colombia the subspecies occurs only in the Caribbean drainage. In Central America this frog occurs mostly on the coastal lowlands; the highest recorded elevation is 560 meters at El Valle, Coclé, Panamá. Throughout most of its range _Hyla microcephala microcephala_ occurs in disturbed habitats--cut-over forests, secondary growth, and pastureland. It does not seem to be an inhabitant of either primary forest or of _Curatella_-savanna. _Specimens examined._--522, as follows: +Costa Rica+: Puntarenas: Golfito, KU 32172-207; 3 km. E Golfito, KU 86399, USC 2757-8; Palmar Sur, KU 64591-608, USC 2650 (14), UU 3907-32; *1.5-2.5 km. ESE Palmar Sur, KU 68293-7 (skeletons), 93957-62; Parrita, USC 8254 (2), 8255, 8256 (4), 8258 (2) [intergrades with _H. m. underwoodi_]; 3 km. NW Piedras Blancas, KU 103689; 6.1 km. NE mouth of Río Tárcoles, USC 818 (2), 6081-2 [intergrades with _H. m. underwoodi_]; Villa Neilly, USC 2651; *1-5 km. WNW Villa Neilly, USC 6182-4, 8003 (4), 8031 (3), 8032; *10.5 km. WNW Villa Neilly, KU 64609-27, 68398 (eggs).