The mature larva and pupa of Otiorhynchus smreczynskii are described and illustrated with complete chaetotaxy for the first time. Five larval instars and the factors for larval growth are determined, and the larval development of this species is comprehensively described. In order to confirm species affiliation, selected larvae were subjected to genetic analysis (mtCOI). Host plants and unique feeding signs of some Entiminae species are presented, and all available data on development are documented and interpreted. Additionally, the morphometry of 78 specimens (48 of O. smreczynskii and 30 of O. rotundus) was examined in order to verify the usefulness of morphological features in distinguishing both species. The female genitalia of both species are illustrated, described and compared with each other for the first time. Finally, the updated distribution of O. smreczynskii is given, and a possible origin of O. smreczynskii and O. rotundus is proposed.
Keywords: COI; Curculionoidea; Entiminae; O. rotundus; Otiorhynchus smreczynskii; adult stage; biology; distribution; larva; morphometry; origin; pupa; weevil.