Taylor (1940a:18) diagnosed this species as having few or no vomerine teeth, no vocal sac, a rather broad and flat head, two large tubercles below the anus, a granular venter, and a green dorsum in life. The specimens on which the description was based are either immature or non-breeding individuals; all were collected from bromeliads growing on cacti near Cojumatlán. Another small, flat-headed hylid from Tepoztlán, Morelos, was described and diagnosed by Taylor (1943b:49) as differing from Hyla smaragdina in having a vocal sac and a broader head. This specimen was named Hylella azteca. Specimens from the coastal region of Michoacán and Colima were referred to Hylella azteca by Peters (1954:7) and Duellman (1958c:8).
Comparison of topotypic Hyla smaragdina and the holotype of Hylella azteca (UIMNH 25044) with the several series of specimens from Michoacán has resulted in the conclusion that all pertain to only one species. Although the type series of Hyla smaragdina consists of immature specimens, the males in that series do possess vocal sacs. Since these were not breeding individuals, the sacs are not well developed. The characters of the anal tubercles and the relative width of the head are of no value in separating the two species. The apparently aestivating individuals comprising the type series of Hyla smaragdina, and the type of Hylella azteca, which also was found in a bromeliad, were green in life. Of the calling males found on the coast of Michoacán, most were yellowish tan when found; two were pale green, but soon changed to pale tan. Calling males from Copuyo and Dos Aguas were pale yellowish tan. Therefore the color of the dorsum is of little significance in distinguishing the two named populations.
Males of Hyla smaragdina have been found calling in the months of June and July from rocky streams; the call is a nasal "haah-haah-haah," repeated quickly and constantly for as long as 30 seconds. As pointed out by Duellman (1958c:9), this breeding behavior is unlike that suggested by Taylor (1943b:51). In Michoacán Hyla smaragdina has been found in tropical semi-deciduous forest, oak forest, and mesquite-grassland at elevations from 150 to 1500 meters.
Hyla smithi Boulenger
Hyla smithi Boulenger, Zool. Rec. Reptilia and Batrachia, 38:33, 1902.—Cuernavaca, Morelos, México.
Aguililla (14); Apatzingán (104); Arteaga; Charapendo (5); Coalcomán (11); El Sabino (44); La Playa (6); Lombardia (2); Nueva Italia (8); Playa Azul; Salitre de Estopilas (2).
This small hylid is abundant in the Tepalcatepec Valley to elevations of about 1000 meters; it was found infrequently on the coastal lowlands. Males call from bushes in and around flooded fields and ditches, from grasses and small herbs in the water and from vegetation overhanging small streams. The call consists of a series of short, high notes, somewhat reminiscent of a katydid's song. In the dry season occasional males were heard calling from irrigated fields near Apatzingán. In the daytime individuals were found in the axils of leaves of the elephant-ear plants (Xanthosoma).
In living individuals the dorsal color usually is uniform pale yellow; often the lateral white stripe is barely visible. The vocal sac is bright yellow, and the iris is pale gold. In some individuals there are scattered dark brown spots or flecks on the back and upper surfaces of limbs. Twenty males from Apatzingán have the following measurements: snout-vent length, 22.8-26.0 (25.0) mm., tibia length, 10.7-13.6 (12.6) mm.; head width, 7.2-8.0 (7.6) mm., head length, 7.1-8.1 (7.7) mm.
Hypopachus caprimimus Taylor
Hypopachus caprimimus Taylor, Univ. Kansas Sci. Bull., 26:526, November 27, 1940.—Agua del Obispo, Guerrero, México.