in
breeding males. Stuart then went on to describe _Ptychohyla
schmidtorum_, a species characterized by the absence of horny nuptial
spines in breeding males. My investigations of these frogs have
revealed the presence of two groups of species. In both groups breeding
males have large ventrolateral glands, but the two groups are easily
separated by four characters. The first group contains, among others,
_Ptychohyla leonhard-schultzei_, _euthysanota_, _spinipollex_, and
another species in the Mesa Central of Chiapas to which I tentatively
apply the name _Ptychohyla macrotympanum_ (Tanner), 1957. This group of
species is characterized by horny nuptial spines in breeding males,
presence of a tarsal fold, a call consisting of a single long note, and
tadpoles having lips not greatly expanded. The second group, as
recognized here, is characterized by the absence of horny nuptial
spines in breeding males, lack of a tarsal fold, a call consisting of a
series of short notes, and tadpoles having greatly expanded lips. In
this group belong _Ptychohyla schmidtorum_ and the two species
described below.

Only the descriptions of the new species are given in this paper;
detailed comparisons, descriptions of osteological features, analyses
of calls, and discussions of relationships are reserved for a
forthcoming review of the entire genus.

In the spring of 1959, collections of amphibians and reptiles were made
in the cloud forests on the northern slopes of the Sierra Madre
Oriental in northern Oaxaca. Among the hylids found, two specimens of a
heretofore unnamed species of _Ptychohyla_ have brilliant red
flash-colors on the groin and thighs; in allusion to these fiery colors
I propose that this species be named:

~_Ptychohyla ignicolor_~ new species

(Plate 25, Fig. 1)

_Holotype._--University of Michigan Museum of Zoology No.
119603, from a stream 6 kilometers south of Vista Hermosa,
Oaxaca, Mexico (1865 meters); obtained on March 31, 1959, by
Thomas E. Moore. Original Number WED 14159.

_Paratype._--UMMZ 119602 from Vista Hermosa, Oaxaca (1500
meters); obtained on March 30, 1959, by William E. Duellman.

_Diagnosis._--A species of the _schmidtorum_-group of
_Ptychohyla_ differing from other known members of the group
in having the diameter of the tympanum less than one-half
the diameter of the eye, no white spot below the eye, no
lateral light stripe, bright green do