_Definition._--Small hylids attaining a maximum snout-vent length of
27 mm. in males and 32 mm. in females; dorsum yellowish tan with brown
markings; thighs uniformly yellow, vocal sac in breeding males yellow;
snout truncate in lateral profile; tympanum distinct, usually slightly
smaller than one-half diameter of eye; vocal sac single, median,
subgular; fingers about one-third webbed; toes webbed nearly to bases
of discs, except only to middle of antepenultimate or base of
penultimate phalanx of fourth toe; tarsal fold weak; inner metatarsal
tubercle low, flat, elliptical; axillary membrane present; pupil
horizontally elliptical; palpebral membrane unmarked; cranial elements
reduced in ossification; sphenethmoid small, short; frontoparietal
fontanelle large; tegmen tympani not extensive; quadratojugal greatly
reduced; anterior arm of squamosal extending only about one-fourth
distance to maxillary; posterior arm of squamosal not having bony
connection with prootic; nasals lacking maxillary processes; medial
ramus of pterygoid not having bony attachment to prootic; maxillary,
premaxilary, and prevomerine teeth present; palatine and parasphenoid
teeth absent; Mentomeckelians ossified; tadpoles having xiphicercal
tails with deep caudal fins and terminal mouth lacking teeth; mating
call consisting of one primary note followed by a series of shorter
secondary notes; haploid number of chromosomes, 15 (known only in _H.
microcephala_ and _H. phlebodes_.)
_Content._--As recognized here the _Hyla microcephala_ group contains
four species, one having two subspecies. An alphabetical list of the
specific and subspecific names that we consider to be applicable to
the _Hyla microcephala_ group are listed below.