e dusky brown, but a few are darker.
In comparison with specimens from the Caribbean lowlands of Central
America, specimens from the Pacific slopes in Costa Rica have a darker
interorbital triangle. In some specimens from the latter area
rugosities are present on the borders of the interorbital triangle, on
the snout, on the upper eyelid, and on the heel. Specimens from the
Caribbean lowlands are less tuberculate, and most individuals from
there lack rugosities on the tarsus. Living individuals from Puerto
Viejo, Heredia Province, Costa Rica, and from the Canal Zone, Panama,
are brown above with a metallic green tint. Rugosities are present on
the posterior edges of the forelimbs in some specimens from throughout
the range. In most respects, specimens from the Canal Zone resemble
those from the Caribbean lowlands of Costa Rica more than they resemble
those from the Pacific lowlands of Costa Rica, but some individuals
from the Canal Zone are less metallic above and have small white spots
dorsally on the body, head, and limbs.

A moderate amount of color change from night to day has been noted. At
night, a male from Puerto Viejo, Heredia Province, Costa Rica, was
grayish tan above with slightly darker markings; the flanks were pale
yellowish green. By day, the dorsum was brown with darker markings, and
the throat was pale gray with white flecks; the rest of the venter was
creamy white. The groin was pale green with black mottling; the
anterior and posterior surfaces of the thighs and inner edges of the
tarsi were greenish yellow with black bars.

TABLE 1.--Geographic Variation in Size and Proportions in Males of
_Hyla boulengeri_. (Means in parentheses below observed ranges.)

=========================================================================
| | Snout-vent| Tibia | |
| | length | length/ |Tympanum/|Foot length/
Locality | N | (mm.) | snout-vent| eye | snout-vent
--------------------+----+-----------+-----------+---------+-------------
Costa Rica: Tilaran | 23 | 37.4-48.7 | 0.52-0.58 |0.62-0.76| 0.39-0.45
| | (43.8) | (0.55) | (0.71) | (0.42)
| | | | |
Costa Rica: Rincon | 10 | 41.4-46.1 | 0.54-0.60 |0.68-0.80| 0.40-0.45
de Osa | | (44.0) | (0.57) | (0.74) | (0.43)
| | | | |