Subfamily Phyllomedusinae Guenther, 1859 Phyllomedusidae Guenther 1859 [Type genus, _Phyllomedusa_ Wagler, 1830]. _Definition._--Moderately small to large hylids having vertical pupils, _n_=13 (2_n_=26) chromosomes, skin containing large amounts of powerful bradykinin-like and physalaemin-like polypeptides, eggs suspended from vegetation above water, and tadpoles have a ventral spiracle sinistral to midline. _Range._--Low and moderate elevations in South and Middle America, including Trinidad, from northern Argentina and northwestern Ecuador to Veracruz and southern Sonora, Mexico. _Content._--Three genera, one of which probably is composite. Genus =Agalychnis= Cope, 1864. _Agalychnis_ Cope, 1864 [Type species, _Hyla moreletii_ Dumeril, 1853, by subsequent designation]. _Definition._--Fingers and toes at least half webbed; terminal discs large; first toe shorter than second and not opposable to others; skin smooth, lacking osteoderms; parotoid glands, if present, poorly developed and diffuse; palpebral membrane reticulate (except in _A. calcarifer_); iris red or yellow; skull shallow, depth less than 40 per cent of length; nasals large; frontoparietal fontanelle large; quadratojugals reduced; prevomerine teeth present. _Range._--Central Veracruz and northern Oaxaca, Mexico, southeastward through Central America to northwestern Ecuador; one species disjunct in Amazonian Ecuador. _Content._--Eight species [synonyms in brackets]: _annae_ (Duellman, 1963); _calcarifer_ Boulenger, 1902; _callidryas_ (Cope, 1862) [_helenae_ Cope, 1885; _callidryas taylori_ (Funkhouser, 1957)]; _craspedopus_ (Funkhouser, 1957); _litodryas_ (Duellman and Trueb, 1967); _moreleti_ (Dumeril, 1853) [_holochroa_ (Salvin, 1861)]; _saltator_ Taylor, 1955; _spurrelli_ Boulenger, 1913. _Remarks._--Savage and Heyer (1967) provided evidence that _A. callidryas taylori_ (Funkhouser) and _A. helenae_ Cope were junior synonyms of _A. callidryas_ (Cope). Genus =Pachymedusa=, new genus Type species, _Agalychnis dacnicolor_ Cope, 1864. _Definition._--Fingers and toes having basal webs and lateral fringes; terminal discs large; first toe shorter than second and not opposable to others; skin smooth or shagreened, lacking osteoderms; paratoid glands present, diffuse; palpebral membrane reticulate; iris golden yellow with black reticulations; skull deep, depth more than 50 per cent of length; nasals large; frontoparietal fontanelle moderately large; quadratojugal robust; prevomerine teeth present. _Range._--Pacific slopes and lowlands from southern Sonora to the Isthmus of Tehuantepec, Mexico. _Content._--Monotypic: _dacnicolor_ Cope, 1864 [_alcorni_ Taylor, 1952]. _Remarks._--The generic name is derived from the Greek _pachy_ meaning thick and the Greek _Medousa_ (Latin, _Medusa_) in reference to _Phyllomedusa_; the sense implied is the heavy body of _Pachymedusa dacnicolor_. Genus =Phyllomedusa= Wagler, 1830