_Description of tadpole._--The following description is based on KU 71716 from Vista Hermosa, Oaxaca, Mexico (Figs. 5C and 6G). Hind limbs small; total length, 39.6 mm.; body length, 11.8 mm.; body length/total length, 29.8 per cent. Body moderately depressed, only slightly wider than deep, in dorsal profile ovoid, widest just posterior to eyes; in lateral profile snout rounded; mouth directed ventrally; eyes small, directed dorsolaterally; nostrils barely protuberant, directed anteriorly, somewhat closer to eye than snout; spiracle sinistral and posteroventrad to eye; anal tube dextral. Tail long and slender; caudal fin low and rounded posteriorly; depth of caudal musculature about one-half greatest depth of caudal fin; musculature not extending to tip of tail. Mouth large; thin fleshy lips greatly expanded and forming large funnel-shaped disc; width of mouth about two-thirds greatest width of body; outer edge of lips having one row of small papillae; inner surface of mouth smooth; scattered large papillae forming one nearly complete row around teeth; other papillae laterally; one large papilla just above each end of first lower tooth-row; beaks moderately developed bearing long, pointed denticulations; no lateral projections on upper beak; tooth-rows 3/3, all short; second and third upper rows subequal in length; first upper row shorter; first lower row equal in length to second and third upper rows; second lower row slightly shorter; third lower row shortest. Body creamy gray with dark brown flecks above and below; mouth colored like body; caudal musculature creamy tan; caudal fin transparent; dark brown streak on anterior third of caudal musculature; rest of tail and all of caudal fin, except anterior two-thirds of ventral fin, heavily flecked with brown; iris silvery bronze color in life. _Variation._--The only other known tadpole, which was collected with the individual described above, differs in having only two upper tooth-rows. The first upper tooth-row seems not to have developed. _Comparisons._--From _P. schmidtorum chamulae_ and _P. s. schmidtorum_, _P. ignicolor_ differs as follows: Tympanum smaller; snout more nearly square; less webbing on toes; internarial region flat instead of depressed; white lateral stripes lacking. _Ptychohyla ignicolor_ and several small and moderate sized hylids are sympatric. From _P. ignicolor_ these hylids can be distinguished as follows: _Hyla dendroscarta_ has a round snout and yellow dorsum; _Hyla erythromma_ has a round snout, green dorsum, white flanks, and a red eye; _Hyla hazelae_ has a tarsal fold, green dorsum, and a black line on the canthus; and _Ptychohyla leonhardschultzei_ has a tarsal fold, brown dorsum, black and white flanks, and horny nuptial spines in breeding males.