The Costarina faunas of Panama and Colombia are revised. Because Chickering described the sexes from his Panamanian collections separately, several of his names based only on females are placed as junior synonyms of names based only on males: C. humphreyi (Chickering) is newly synonymized with C. recondita (Chickering), as are C. belinda (Chickering) with C. intempina (Chickering), C. rigida (Chickering) with C. abdita (Chickering), C. silvatica (Chickering) with C. dura (Chickering), and C. improvisa (Chickering) with C. seclusa (Chickering). The Costa Rican species C. pittier Platnick and Berniker is newly recorded from Panama. Nine new species are described from Panama (C. sorkini, cerrocol, bocas, chiriqui, clara, fortuna, almirante, dybasi, and tskui), as are 11 from Colombia (C. sasaima, suiza, otun, choco, yotoco, saladito, antonio, anchicaya, gorgona, helechal, and taraira). Previous studies on more northern species are supplemented; newly available collections from Nicaragua reveal the presence there of two new species (C. kilambe and diablo), and locality records are provided for the Costa Rican members of the genus.