RESUMO
BACKGROUND: The largest number of species of the widespread and highly diverse micromoth genus Ypsolopha Latreille, 1796 (Lepidoptera, Yponomeutoidea, Ypsolophidae) is known from the Northern Hemisphere. Only seven species have been described from the Neotropical Region, two of which occur in Chile. NEW INFORMATION: The adult stage of Ypsolophachicoi sp. n. from the arid highlands of the western slopes of the Andes of northern Chile is described and illustrated. Its larvae feed on the native shrub Muehlenbeckiafruticulosa (Walp.) Standl. (Polygonaceae). The morphology of the genitalia of Y.chicoi sp. n. resembles that of the only congeneric known to occur in the same geographic area, Y.moltenii Vargas, 2018, whose larvae feed on Adesmiaverrucosa Meyen (Fabaceae). Besides using different host plants, the two species can be accurately separated, based on morphological differences in female and male genitalia.