Holotype. University of Illinois Museum of Natural History No. 49339 from Vista Hermosa, Oaxaca, Mexico (elevation 1500 meters), obtained by O. C. Van Hyning. Diagnosis. A species of Hyla having a dermal fringe along the outer edge of the forearm and along the outer edge of the tarsus, differing from other known fringe-limbed hylids by having the skin of the dorsum smooth and by having a large prepollex bearing many moderatesized horny spines. Description of Holotype. Adult male having a snout-vent length of 57.0 mm.; tibia length, 30.5 mm.; tibia length/snout-vent length, 53.5 per cent; foot length (measured from proximal edge of inner metatarsal tubercle to tip of longest toe), 26.5 mm.; foot length/snout-vent length, 46.5 per cent; head length, 19.8 mm.; head length/snout-vent length, 34.7 per cent; head width, 22.3 mm.; head width/snout-vent length, 39.1 per cent; diameter of eye, 5.6 mm.; diameter of tympanum, 4.3 mm.; tympanum/eye, 76.8 per cent; interorbital distance, 7.1 mm.; interorbital distance/head width, 30.8 per cent; width of eyelid, 5.7 mm.; eyelid/head width, 25.5 per cent. Snout, in lateral profile, truncate, in dorsal profile obtusely rounded (Fig. 1); canthus pronounced, rounded, not angular; loreal region concave; lips thick and flaring; nostrils barely protuberant; internarial distance, 4.2 mm.; top of head flat; interorbital distance greater than width of eyelid; a heavy dermal fold from posterior corner of eye above, and concealing upper part of, tympanum, and curving ventrally to insertion of forearm; tympanum round, its diameter greater than distance from eye. Forearm robust; strong fold across wrist; dermal fringe