_Hyla misera_ possibly is allied to other small yellowish tan South American _Hyla_ that lack dark pigmentation on the thighs. Probable relatives are _Hyla elongata_, _minuta_ (with _goughi_, _pallens_, _suturata_, _velata_, and possibly others as synonyms), _nana_, and _werneri_. The consideration of the interspecific relationships of these taxa is beyond the scope of this paper, but we can say that each of these species has a pale yellowish tan dorsum, relatively broad dorsolateral brown stripe, and narrow longitudinal brown lines or irregular marks on the dorsum. Furthermore, examination of the skulls of _elongata_, _nana_, and _werneri_ reveals that they are like _misera_ and _microcephala_ in the nature of the frontoparietal fontanelle and in having a greatly reduced quadratojugal. Thus, on the basis of cranial and external characters the _Hyla microcephala_ group can be associated with _Hyla misera_ and its apparent allies in South America. This association can be only tentative until the mating calls, tadpoles, and chromosome numbers of the South American species are known. Among the Middle American hylids, only the _Hyla microcephala_ group and _H. ebraccata_ have a haploid number of 15 chromosomes (Duellman and Cole, 1965). All other New World _Hyla_, for which the number is known, have a haploid number of 12; the only other _Hyla_ having 15 is a Papuan _Hyla angiana_ (Duellman, 1967). _Hyla ebraccata_ occurs in the humid tropical lowlands of Middle America and the Pacific lowlands of northwestern South America. It is the northernmost, and only Central American, representative of the _Hyla leucophyllata_ group, which is diverse (about 10 species currently recognized) and widespread in tropical South America east of the Andes. This group is characterized by having broad, flat skulls with larger nasals and more ossification of the frontoparietals than in the _Hyla microcephala_ group. The quadratojugal is present as a small anteriorly projecting spur that does not connect with the maxillary. Externally, the _Hyla leucophyllata_ group is characterized by having a well-developed axillary membrane, uniformly yellow thighs, and a dorsal color pattern in many species consisting of a dark lateral band, a pale dorsolateral band or dorsal ground color, and a large middorsal dark mark. In some species, the dorsal pattern consists of small dark markings or is nearly uniformly pale. At least in the Central American _Hyla ebraccata_, the mating call consists of a single primary note followed by a series of shorter secondary notes, the tadpoles have xiphicercal tails and lack teeth, and the haploid number of chromosomes is 15. On the strength of these observations it seems imperative to consider the _Hyla leucophyllata_ group as a close ally to the _Hyla microcephala_ group. Successful artificial hybridization supports the close relationship of _H. m. microcephala_ and _phlebodes_; partial success of artificial hybridization of these