Since the cloud forests inhabited by _Ptychohyla_ are daily bathed in clouds and have a fairly evenly distributed rainfall throughout the year, the frogs living in these forests are active throughout the year. At least some of the species evidently have a long breeding season, for I found calling males of _P. leonhardschultzei_ in February, March, and August, and found tadpoles in February, March, June, and August. Tadpoles of the various species have been obtained throughout much of the year, as follows: _P. euthysanota euthysanota_, February, March, May, and July; _P. euthysanota macrotympanum_, March, June, and August; _P. spinipollex_, February, March, April, June, July, and August; _P. schmidtorum schmidtorum_, March, May, June, July, and August; _P. schmidtorum chamulae_, June and August; _P. ignicolor_, June. I suspect that this temporal distribution more accurately reflects the seasonal activities of collectors than of the frogs. Calling frogs usually are on vegetation adjacent to or overhanging streams; some calling males of _P. spinipollex_ were on rocks in or by streams. Clasping pairs of _P. euthysanota_ and _P. schmidtorum_ were observed on vegetation by streams. Despite intensive search, no eggs were found. It is doubtful if _Ptychohyla_ deposit eggs on vegetation overhanging streams, as do centrolenids and _Phyllomedusa_, for egg-clutches of these frogs are easily found. Possibly the eggs are laid separately on vegetation above the stream, in which case they could be overlooked easily. In streams where _Ptychohyla_ and other hylid tadpoles occur, empty egg capsules have been found on the lee sides of rocks, but there is no way to determine which species laid the eggs. Numbers of eggs were counted in gravid females; the largest eggs have diameters ranging from 2.5 to 3.0 mm. The smaller species, comprising the _Ptychohyla schmidtorum_ group, have fewer eggs than do the larger species. Numbers of eggs found in females of the various species are: _P. euthysanota euthysanota_, 108; _P. euthysanota macrotympanum_, 136, 160; _P. leonhardschultzei_, 141; _P. spinipollex_, 119, 134, 143; _P. schmidtorum schmidtorum_, 59, 61, 90; _P. schmidtorum chamulae_, 60, 71, 89. Duration of the larval stage is unknown. Metamorphosing young have been found from May through August. From two to six completely metamorphosed young are available for each of the species, except for _P. ignicolor_ of which none is available. The smallest young frog is a _P. euthysanota_ having a snout-vent length of 14.2 mm.; the largest young frog is a _P. schmidtorum schmidtorum_ having a snout-vent length of 17.0 mm. PHYLOGENY OF PTYCHOHYLA