The calls of the allopatric species _S. puma_ and _S. sila_ are not greatly different. _Smilisca sordida_ has a distinctive call and occurs sympatrically with _S. puma_ and _S. sila_. In the streams in southern Costa Rica _S. sordida_ and _S. sila_ breed synchronously, but the high-pitched modulated call of the former is notably different from the lower, unmodulated call of _S. sila_. The data indicate that the calls of related sympatric species differ more than the calls of related allopatric species. We postulate that these differences evolved to support the reproductive isolation of the sympatric species. The data are insufficient to determine geographic variation in the calls and to determine if differences in the calls are enhanced in areas of sympatry as compared with the allopatric parts of the ranges. _Other calls._--As stated previously, there is no direct evidence of territoriality in _Smilisca_; we have heard no calls that can be definitely identified as territorial. Single notes of _S. baudini_, _phaeota_, and _sila_ have been heard by day, just prior to rains, or during, or immediately after rains. Such calls can be interpreted as "rain calls," which are well known in _Hyla eximia_ and _Hyla squirella_. Distress calls are known in several species of _Rana_ and in _Leptodactylus pentadactylus_; such calls result from the rapid expulsion of air over the vocal cords and with the mouth open. Distress calls have been heard from _S. baudini_. At Charapendo, Michoacan, Mexico, a male that had one hind limb engulfed by a _Leptodeira maculata_ emitted several long, high-pitched cries. A clasping pair of _S. baudini_ was found in a bush at the edge of a marshy stream 2 kilometers northeast of Las Canas, Guanacaste Province, Costa Rica. When the pair was grasped, the female emitted a distress call. Eggs Eggs of _S. baudini_, _cyanosticta_, and _phaeota_ have been found in the field, and eggs of _S. sila_ have been observed in the laboratory. The eggs of _S. puma_ and _sordida_ are unknown. Insofar as known, _Smilisca baudini_ is unique in the genus in depositing the eggs in a surface film. Each egg is encased in a vitelline membrane, but individual outer envelopes are lacking. The eggs are small; the diameter of recently-deposited eggs is about 1.3 mm. and that of the vitelline membrane is about 1.5 mm. The eggs of _S. cyanosticta_ and _phaeota_ are deposited in clumps, and the eggs are larger than those of _S. baudini_. Diameters of eggs of _S. cyanosticta_ are about 2.3 mm., and those of the outer envelopes are about 4.0 mm. Artificially fertilized eggs of _S. sila_ raised in the laboratory have diameters of about 2.4 mm.; the diameter of the outer envelopes is about 4.9 mm.