I am indebted to the following persons for permitting me to examine
specimens in their care: Miguel Alvarez del Toro, Museo Zoologia de
Tuxtla Gutierrez, Mexico (MZTG); Charles M. Bogert and Richard G.
Zweifel, American Museum of Natural History (AMNH); Doris M. Cochran,
United States National Museum (USNM); Norman Hartweg and Charles F.
Walker, University of Michigan Museum of Zoology (UMMZ); Robert F.
Inger, Chicago Natural History Museum (CNHM); Hobart M. Smith,
University of Illinois Museum of Natural History (UIMNH); Heinz
Wermuth, Zoologisches Museum Berlin (ZMB); and Ernest E. Williams,
Museum of Comparative Zoology (MCZ). The abbreviations following names
of institutions will be used throughout the text; the Museum of
Natural History at the University of Kansas is abbreviated KU.
Throughout my work on these frogs I have profited from discussions
with L. C. Stuart, who has made many valuable suggestions and with his
characteristic generosity has placed at my disposal his extensive
collections of tadpoles from Guatemala. For his aid I am indeed
grateful. I am grateful to Thomas E. Moore for tapes of breeding calls
of two species.
My own field work was made more enjoyable and profitable through the
assistance of Dale L. Hoyt, Craig E. Nelson, Jerome B. Tulecke, and
John Wellman, all of whom spent many hours in often unsuccessful
attempts to collect specimens and record breeding calls of
_Ptychohyla_. I am indebted to many residents of Mexico, Guatemala,
and El Salvador for permission to work on their land and for providing
shelter, food, and guides. I am especially grateful to Mr. and Mrs.
Horatio Kelly of "Colegio Linda Vista" at Pueblo Nuevo Solistahuacan,
Chiapas, for a pleasant stay at their school; Jordi Julia Z. of the
Comision del Papaloapan, Ciudad Aleman, Veracruz, for arranging for
field work in northern Oaxaca in 1959; Walter Hannstein and Lothar
Menzel for the use of facilities at Finca La Paz, Guatemala, in 1960;
Alan Hempstead for the use of facilities at Finca Los Alpes, Guatemala
in 1960 and 1961; and Julio Aguirre C. of the Instituto Tropical de
Investigaciones Cientificas, San Salvador, El Salvador, for providing
comfortable working quarters and transportation and guides to the
mountains in northern El Salvador. Without the cheerful efforts of
Jorge A. Ibarra, Director of the Museo Nacional de Historia Natural in
Guatemala, my field work would have been greatly restricted during
politically precarious times in that country. Permits to collect in
Mexico were furnished by the late Luis Macias Arellano of the
Direccion General de Caza. Each of these individuals has my profound
thanks for his indispensable aid.
Field work on hylid frogs in Middle America has been supported by the
National Science Foundation, Grant NSF-G9827, and this is the 9th
publication on the results of study of the material from America.