EN
The egg, three larval instars and pupa of Hesperus rufipennis (Gravenhorst) are described for the first time, with the illustrations of structural features provided. Differences in the morphological structure of its larval instars (L₁₋₃) cover: the number of setae on profemur and protibia, number of setae on tarsungulus, chaetotaxy of abdominal tergites, the structure of antenna and urogomphi, body colour and measurements. Diagnostic characters of immature stages of H. rufipennis are listed. Modifications of the keys to known eggs, larvae and pupa of the European Staphylininae species are proposed. Some data on its biology (life cycle, duration of immature stages, ecological preferences) are also given. It is a univoltine species with summer larvae and wintering imagines. Considering its environmental preferences and biology, this rove beetle may be of essential importance as a good umbrella species and environmental state indicator as well.