A peculiar new species of gall-inducing, clearwing moth (Lepidoptera, Sesiidae) associated with in the Atlantic Forest.

Larvae of most clearwing moths (Lepidoptera, Sesiidae) are endophagous borers of many angiosperms, including their fruits, stems, and roots. Their localized feeding may lead to swellings on those plant parts, but whether the structures produced should be considered true galls is still controversial. In this study we describe a peculiar sesiid moth, whose larvae induce unusual, external galls on (Vell.) Cogn. (Cucurbitaceae) in the Atlantic Forest of southernmost Brazil. The adults, egg, larva, pupa and the gall are described and illustrated based on light and scanning electron microscopy. Galls are cylindrical and unilocular; they are induced individually on axillary buds of the stem. Unlike larvae of other sesiids, those of lack abdominal pseudopodia, and show reduced stemata and chaetotaxy. Pupation occurs inside the gall, after having overwintered in the last larval instar. A maximum likelihood tree constructed based on mitochondrial DNA (COI) sequences showed that is monophyletic and has an average distance of 13% to species of . The genera Le Cerf, 1916 stat. rev., Le Cerf, 1916 stat rev., and Le Cerf, 1917 stat. rev. are restored from synonyms of Hübner, 1819 ["1816"].