In preserved specimens the dorsal ground color varies from yellowish tan to grayish brown. All specimens have dark brown dorsal markings in the form of a pair of dorsal stripes, variously modified (Pl. 7A). In some specimens, such as KU 91716, the stripes are discrete and extend from the postorbital region nearly to the vent. In most specimens the stripes are connected by a transverse mark in the scapular region and in many others also by a transverse mark in the sacral region. In some specimens the stripes are fragmented posteriorly; fragmentation is extreme in KU 30300, in which the dorsal pattern consists of two series of dark longitudinal dashes. The other extreme is a nearly complete fusion of the stripes, as in KU 91714. A dark brown interorbital bar usually extends onto the eyelids, but in some specimens this is reduced to a short V-shaped mark or small spot between the eyes. There is no dark post-tympanic mark, but dark brown pigment forms a venated pattern from the axilla to the mid-flank; the inguinal region is white, finely mottled with dark brown. The dorsal surfaces of the hind limbs are colored like the body and have two or three dark brown transverse marks on the thighs, three to five marks on the shanks, and one or two marks or irregularly arranged dark flecks on the tarsi. The anterior and posterior surfaces of the thighs are pale tan to brown. The webbing of the feet is tan to grayish brown. A narrow white labial stripe, white anal stripe, and narrow white stripes on the tarsi and outer edges of the forelimbs are invariably present. The ventral surfaces are creamy white. In life the dorsum is tan or pale brown with dark brown markings. Some individuals have scattered metallic green flecks on the dorsum. The flanks are mottled dark brown and creamy white. The posterior surfaces of the thighs are dark brown. The vocal sacs are grayish brown, and the iris is a deep bronze color. _Natural History._--_Smilisca puma_ inhabits humid lowland tropical forests having more or less evenly distributed rainfall throughout the year. The equable climatic conditions seemingly permit these frogs to be active throughout most of the year. Taylor (1952:846) found calling males at Batan, Costa Rica, on July 20, 1951. We found the species breeding near Puerto Viejo, Costa Rica, on February 19, June 18, July 13, and July 31. Specimens of calling males from Costa Rica in the collection at the University of Southern California were obtained in February at La Fortuna, on August 22 at Los Diamantes, on August 30 at Jabillos, and on September 5 at La Lola. Gravid females were collected in June, July and August.