Ten new species from the Patagonian Andes (Argentina and Chile), mostly belonging to a newly designated Stigmella purpurimaculae group (Lepidoptera: Nepticulidae).

Ten new Stigmella Schrank species are described: Stigmella purpurimaculae Remeikis & Stonis, sp. nov., S. cana Remeikis & Stonis, sp. nov., S. truncata Remeikis & Stonis, sp. nov., S. sceptra Remeikis & Stonis, sp. nov., S. concreta Remeikis & Stonis, sp. nov., S. pseudoconcreta Remeikis & Stonis, sp. nov., S. quadrata Remeikis & Stonis, sp. nov. (all belonging to the newly designated S. purpurimaculae group), and S. semilactea Remeikis & Stonis, sp. nov., S. brutea Remeikis & Stonis, sp. nov., S. pseudodigitata Remeikis & Stonis, sp. nov. (not attributed to a species group) are described from the Andes (Patagonia: Argentina and Chile). For the species of the purpurimaculae group, a partial reduction of phallus, dentate cornuti, and strong development of utriculus (which can be equal or longer of the corpus bursae) are characteristic. Some of the species of the purpurimaculae group were collected near Nothofagus pumilio (Poepp. & Endl.) Krasser, Nothofagaceae, but there is still no confirmation that Nothofagus is a host-plant. All new Stigmella species are illustrated with photographs and drawings of the adults and genitalia.