Redescription of the freshwater amphipod Hyalella faxoni from Costa Rica (Crustacea: Amphipoda: Hyalellidae)

Hyalella faxoni Stebbing, 1903 from Costa Rica is redescribed. The species was previously in the synonymy of Hyalella azteca (Saussure, 1858). The morphological differences between these two species are discussed.

A new species of Hyalella from the Andes in Perú (Crustacea: Amphipoda: Hyalellidae)

Hyalella pauperocavae n. sp. from Huancayo, Perú, is described. Five other epigean freshwater amphipods have been described from Peru (excluding Lake Titicaca), but the lack of type material and poor descriptions do not allow the assignment of the species described here to any of the names known for the area.