MlJS. COMP. 200L. LIBRARY OCCASIONAL PAPERS MAR 24 1972 of the MUSEUM OF NATURAJ^^jJ^I^TORY The University of Kansas Lawrence, Kansas NUMBER 7, PAGES 1-19 MARCH 15, 1972 NEW TREE FROGS OF THE GENUS HYLA FROM THE CLOUD FORESTS OF WESTERN GUERRERO, MEXICO By Kraig Adler^ and David M. Dennis" Because of the difficulty of travel in the mountainous regions of western Guerrero, this major area of uplift has remained one of the poorest known in Mexico. Therefore, it is not surprising that a number of new species of amphibians and reptiles has been dis-covered in this region; only a few of these species have been de-scribed to date. These montane species occur in cloud forests in the Sierra Madre del Sur, which is Hanked by the arid Rio Balsas basin to the north and west and by the Pacific Ocean to the south. This mountain range extends eastward into Oaxaca; however, sev-eral high but dry valleys interrupt the crest and create discontinui-ties in the cloud forest. The two new frogs described below are rep-resentatives of two species groups. Although representatives of both of these groups occur in the Sierra Madre del Sur in Oaxaca, the apparently closest known relatives of the two new species occur to the northeast, in the high mountains between Mexico and Vera-cruz. Hyla trux new species (Figure 1; Plate 1) Holotype.— Adult male, KU 137551, from 11.4 km (by road) southwest of Puerto del Gallo, Guerrero, Mexico [about 35 km 1 Department of Biology, University of Notre Dame, Notre Dame, Indiana 46556. 2 College of Biological Sciences, The Ohio State University, Columbus, Ohio 43210.