_Life History._--This frog has been found along streams in cloud forests and in pine-oak forest. Males call from vegetation along the stream or from rocks in and at the edge of the stream. The call is a single, long, soft "wraack," repeated at intervals of anywhere from several seconds to three or four minutes. Each note has a duration of 0.62 to 0.95 of a second and a rate of 76 to 78 pulses per second; the dominant frequency falls between 2700 and 2800 cycles per second (Pl. 11C). Tadpoles were found in several streams in northern Oaxaca. A tadpole having a total length of 21.1 mm. has three upper and four lower tooth-rows well developed; the fourth upper and fifth lower rows are weakly present, and the sixth lower row has not started to develop. Two metamorphosed young have snout-vent lengths of 15.2 and 15.5 mm. _Remarks._--Four specific names have been applied to this species. Ahl (1934:185) based his description of _Hyla leonhardschultzei_ on a small, poorly preserved female. Taylor (1944:41) proposed the generic name _Ptychohyla_ for a species (named therein as _P. adipoventris_) of hylid having ventrolateral glands and horn-covered nuptial spines. Obviously, Taylor was unaware that _Hyla leonhardschultzei_ was the same species. Earlier Taylor (1937:46) described _Hyla pinorum_. The types of all of these species came from the Pacific slopes of the Sierra del Sur in Guerrero. Examination of the types and other available specimens shows that they are representatives of a single species. The type of _Hyla pinorum_ is an immature male having a snout-vent length of 26.7 mm. All of these specimens have the square snout and black and white flanks characteristic of _Ptychohyla leonhard-schultzei_. Although Shannon (1951:473) based his description of _Hyla milleri_ on a male having well-developed ventrolateral glands, he overlooked the presence of these glands in his description and discussion of relationships. The acquisition of more specimens from northern Oaxaca has shown that _Hyla milleri_ is the same as _Ptychohyla leonhardschultzei_. _Distribution._--This species is known from pine-oak forest and cloud forest on the Pacific slopes of the Sierra Madre del Sur in Guerrero and Oaxaca and from the Atlantic slopes of the Sierra Madre Oriental in northern Oaxaca. Specimens have been collected at elevations between 700 and 1650 meters. Probably the species occurs in humid forests at similar elevations around the eastern end of the Mexican Highlands in Oaxaca.