Updated descriptions of the last larval instar (based on the larvae and exuviae) and first detailed description of the pupa of Ctesias(s. str.)serra (Fabricius, 1792) (Coleoptera: Dermestidae) are presented. Several morphological characters of C.serra larvae are documented: antenna, epipharynx, mandible, maxilla, ligula, labial palpi, spicisetae, hastisetae, terga, frons, foreleg, and condition of the antecostal suture. The paper is fully illustrated and includes some important additions to extend notes for this species available in the references. Summarised data about biology, economic importance, and distribution of C.serra are also provided. The comparison of larval characteristics for some of the genera of Dermestidae co-occurring with Ctesias is presented. A key for identification of these genera is also provided.