Three new species of Notidobiella Schmid (Insecta: Trichoptera) are described from South America: Notidobiella amazoniana sp. n. (Brazil), N. brasiliana sp. n. (Brazil), and N. ecuadorensis sp. n. (Ecuador). In addition, the 3 previously described species in the genus, N. chacayana Schmid, N. inermis Flint, and N. parallelipipeda Schmid, all endemic to southern Chile, are redescribed and illustrated, including the females of each species for the first time, and a key to males of the species in the genus is provided. The ccurrence of Notidobiella in Brazil and Ecuador represents a significant extension of the range of thegenus beyond southern Chile where it was previously thought to be endemic. The biogeography of Sericostomatidae and other austral South American Trichoptera is reviewed. The occurrence of the family in South America may not be part of a “transantarctic” exchange, but instead represent an earlier dispersal to the region. The distribution of Notidobiella in tropical South America likely represents recent dispersal from southern South America to the north.