LAUSR

Simple Summary We studied small, dully coloured grass-miner moths (Elachistidae, Elachistinae). This is a large subfamily widely distributed throughout the world, but only a few species are known in the Neotropics. To facilitate further exploration, we reviewed one of nineteen species group within the largest genus, Elachista, along with identification keys of species. The E. praelineata species group now comprises of 37 described species, which are distributed in the Americas, Africa, Asia, and Australia. Neotropical species of the group are still underexplored, especially compared with that of Palearctic and Nearctic regions. So far only five species are known to belong to this group, mainly from the Ecuadorian Andes. In this study, we aimed to review and update information on the E. praelineata species group in the Neotropics. Here, we describe in detail a new species Elachista stonisi sp. nov. from western Bolivia. The female of E. albisquamella Zeller, 1877 is described for the first time and the female of E. lata Sruoga, 2010 is associated with the male. The description of new species and the association of females with males are supported morphologically and are confirmed by analysis of partial sequences of mitochondrial COI. Abstract Neotropical species of the Elachista praelineata species group are reviewed. Five species are recognized in the Neotropics. A new species, Elachista stonisi sp. nov., and female of E. albisquamella Zeller, 1877 are described and illustrated with photographs of the adults, some of the immature stages, female genitalia, and leaf mines. The female of E. lata Sruoga, 2010 is associated with the male based on morphology and the comparison of partial mitochondrial COI sequences. Identification keys to the Neotropical species of E. praelineata species group, based on male and female genitalia, are provided.