Morphological characters of the immature stages of Tychius (Apeltarius) amplicollis Aubé, 1850 (Coleoptera, Curculionidae, Curculioninae, Tychiini), supported by molecular and biological data, suggest that Apeltarius Desbrochers des Loges, 1873 is a new synonym of Tychius Germar, 1817

<i>Tychius</i> is a speciose and widespread weevil genus, whose phylogenetic relationships are largely unknown. Here we assess the validity of the subgenus <i>Apeltarius</i> using an integrative approach combining larval morphology and molecular data. The mature larva and pupa of Tychius (Apeltarius) amplicollis Aubé, 1850 are described and illustrated in detail for the first time. Comparisons with known immature stages of several species of <i>Tychius</i> s. str. reveal that the larva and pupa of <i>T. amplicollis</i> exhibit all diagnostic features characteristic of the genus <i>Tychius</i>, showing closest affinity to T. (Tychius) quinquepunctatus (Linnaeus, 1758). Phylogenetic analysis of a fragment of the mitochondrial cytochrome c oxidase subunit I gene confirms their close relationship and supports the inclusion of <i>T. amplicollis</i> in the genus <i>Tychius</i>. Newly obtained biological data show that the life history and host-plant associations of <i>T. amplicollis</i> match those of other <i>Tychius</i> species, with Fabeae (Fabaceae) as hosts. Based on this evidence, we propose that <i>Apeltarius</i> be treated as a junior subjective synonym (<b>syn. nov</b>.) of <i>Tychius</i>. Because there are no other subgenera in the genus <i>Tychius</i> we propose the following combinations: <i>Tychius amplicollis</i> Aubé, 1850; <i>Tychius multilineatus</i> (Desbrochers des Loges, 1873); <i>Tychius quinquelineatus</i> Tournier, 1874; <i>Tychius strigulatus</i> (Desbrochers des Loges, 1875).