_Comparisons._--_Ptychohyla chamulae_ resembles _P. schmidtorum_ in color pattern and body proportions, but the ground color of _schmidtorum_ is chocolate brown and not green as in _chamulae_. Also, in _schmidtorum_ the webbing and posterior surfaces of the thighs are pale cream-color in preserved specimens as contrasted with tan in _chamulae_. In living _schmidtorum_ the iris is bright red, not reddish bronze as in _chamulae_. The ventrolateral glands in _schmidtorum_ more closely approximate one another midventrally than in _chamulae_. It is conceivable that these populations are subspecifically related; _schmidtorum_ occurs in the same kind of habitat as does _chamulae_, but is known only from the Pacific slopes of southeastern Chiapas and southwestern Guatemala, whereas _chamulae_ is known only from the Atlantic slopes of the Mesa Central in north-central Chiapas. Both of these species differ from _Ptychohyla ignicolor_ in having a relatively larger tympanum, more webbing on the foot, different arrangement of anal tubercles, and different coloration. _Description of Tadpole._--Six tadpoles having fully developed mouth parts have body lengths of 5.5 to 11.9 mm. and total lengths of 17.3 to 44.0 mm. The following description is based on a tadpole (KU 58199) having small hind limbs, a body length of 10.5 mm., and a total length of 39.0 mm. Body ovoid, only slightly flattened dorsally and ventrally (Fig. 1); body only slightly deeper than wide; eyes directed dorsolaterally and slightly protuberant; nostrils small. Tail long and slender; greatest depth of tail-musculature two-thirds greatest depth of tail-fin; tail-musculature extending nearly to tip of tail-fin. Mouth directed anteroventrally; thin fleshy lips greatly expanded and forming large suckerlike disc; width of mouth greater than width of snout and nearly as wide as body. Outer edge of lips having small papillae; inner surface of mouth smooth; scattered large papillae, seemingly in rows, around teeth and beak (Fig. 2). Tooth rows 3/3; the upper rows subequal in length; upper rows one and three interrupted medially; lower rows one and two about equal in length to upper rows; third lower row short. Upper beak heavy and horn-covered. [Illustration: FIG. 1. Tadpole of _Ptychohyla chamulae_ (KU 58199). × 2.5.] [Illustration: FIG. 2. Mouthparts of tadpole of _Ptychohyla chamulae_ (KU 58199). × 16.] Color (in alcohol) dark brown over entire body and tail-musculature; a white area near base of tail, and a dark streak on anterior one-fourth of tail; tail-fin transparent having brown blotches.