Hyla microcephala microcephala Cope
Hyla microcephala Cope, Proc. Amer. Philos. Soc., 23:281, February 11, 1886 [Syntypes.—USNM 13473 (2 specimens, now lost) from Chiriquí, Panamá; Mr. MacNeil collector]; Bull. U.S. Natl. Mus., 32:14, 1887. Günther, Biologia-Centrali Americana, Reptilia and Batrachia, p. 265, June, 1901. Dunn, Occas. Papers Boston Soc. Nat. Hist., 5:413, October 10, 1931; Occas. Papers Boston Soc. Nat. Hist., 8:72, June 7, 1933. Stebbins and Hendrickson, Univ. California Publ. Zool., 56:524, February 17, 1959. Fouquette, Evolution, 14:484, December 16, 1960. Busack, Copeia, 2:371, June 21, 1966.
? Hyla cherrei Cope, Proc. Acad. Nat. Sci. Philadelphia, 1894, p. 195, 1894 [Holotype.—location unknown, apparently lost; type-locality: "Alajuela, Costa Rica;" R. Alfaro collector]. Günther, Biologia Centrali-Americana: Reptilia and Batrachia, p. 264, June, 1901. Taylor, Univ. Kansas Sci. Bull., 35:846, July 1, 1952.
Hyla underwoodi, Ruthven, Misc. Publ. Mus. Zool., Univ. Michigan, 8:55, September 15, 1922. Barbour, Proc. New England Zool. Club, 10:31, March 2, 1928.
Hyla microcephala microcephala, Smith, Herpetologica, 7:185, December 31, 1951. Taylor, Univ. Kansas Sci. Bull., 39:23, November 18, 1958.
Diagnosis.—Brown lateral stripe narrow, extending from nostril along canthus, along upper edge of tympanum to groin, bordered above by narrow white line; pair of dark brown longitudinal lines on dorsum extending to vent; shanks having dark longitudinal line or flecks, no transverse bars; interorbital dark mark lacking.
Description and Variation.—The color pattern is nearly constant. Of 103 males from the Canal Zone, all lack an interorbital dark bar, and all have a dark longitudinal line on the dorsal surface of the shank and a narrow lateral dark stripe, bordered above by a narrow white line, extending to the groin. The longitudinal dark lines on the dorsum are continuous to the groin in 95 specimens and fragmented in two specimens. In two others the lines converge and fuse in the scapular region, and in four specimens auxiliary, fragmented lines are present dorsolaterally.
In all specimens from southeastern Costa Rica (Golfito, Palmar Sur, and Villa Neilly) the pattern is constant, except that in about 10 per cent of the specimens the longitudinal line on the dorsal surface of the shank is replaced by a row of brown flecks.
Of the limited number of Colombian specimens examined, all are patterned normally, except three from Sautata, Chocó, three from Curumani, and three from Arcataca, Magdalena, which have flecks on the dorsal surfaces of the shanks, and one from Espinal, Tolima, which has no markings on the shanks.
When active at night most individuals are pale yellowish tan dorsally; the white dorsolateral line is noticeable, but the brown lateral stripe, dorsal brown lines, and lines on shanks are so pale that often they are barely discernible. By day the dorsum changes to tan or pale reddish brown; the stripes are dark brown, and the dorsolateral stripe that is white at night becomes creamy yellow ([Pl. 13]). Small brown flecks are present on the dorsum of most individuals. The venter always is white, and the iris is pale bronze with a brown tint immediately anterior and posterior to the pupil. In breeding males the vocal sac is pale yellow.