s were recorded in the field on Magnemite
and Uher Tape Recorders by Dr. Duellman in the course of his work on
the hylid frogs of Middle America--supported by grants from the
National Science Foundation (G-9827 and GB-1441). These recordings,
plus those borrowed from other institutions, provided 50 tapes for
analysis of the mating calls. The calls were analyzed on a Vibralyzer
(Kay Electric Company).

THE HYLA RUBRA GROUP

_Definition._--The species forming the group are small to moderate-sized
tree frogs (maximum snout-vent length of males of various species 20-49
mm.), distinguished from other groups in the genus _Hyla_ as follows:
Brown, grayish brown, or yellowish tan above; thighs plain, marbled
with dark brown, or having vertical bands; vocal sac single, median,
subgular; snout flat, protruding, rounded or pointed; webbing between
fingers reduced or absent; web between first and second toes reduced to
fringe on second toe, rest of toes about half webbed; tarsal fold
reduced or absent; shanks robust; inner metatarsal tubercle larger than
outer; prevomerine teeth on transverse ridges between small to large
sized choanae; skull generally longer than wide; nasals large (length
more than 40 per cent total length of skull) and having pointed
maxillary processes; maxillary bearing small ventromedial palatine
process; quadratojugal slender, always joined to maxillary by bony
suture; auditory region of prooetic slender and short; delicate
spatulate columella ventral to crista parotica, broad basally,
compressed anterolaterally, slightly rounded distally; anterior arm of
squamosal extending about half distance to maxillary; sphenethmoid
wider than long; frontoparietal fontanelle present or absent;
prevomerine, premaxillary, and maxillary teeth present; prevomer with
two lateral processes forming incomplete bony margin to internal nares;
tadpoles having pointed xiphicercal tail, snout short, rounded; 2/3
tooth rows; dorsal fin deeper than ventral fin; sinistral spiracle;
short dextral anal tube not reaching edge of ventral fin; mating calls
consisting of single long note or series of short notes.

_Composition._--This group contains about 24 currently recognized
species, most of which occur in Brazil. Only five species--_boulengeri,_
_elaeochroa_, _foliamorta_, _rubra_, and _staufferi_ with two
subspecies--occur in Central America. _Hyla boulengeri_ and _rubra_ are
widespread in South America, and _foliamorta_ occ