Una nuova specie del genere Melisia Lombardini 1944 associata a coleotteri passalidi (Acarina, Sarcoptiformes). - In view of a next revision of the genus Melisia, in this first note M. samsinaki n. sp. is described from material found on the elitrae of the Passalid beetle Aceraius helferi Kuvert from Cambogia. M. samsinaki n. sp. resembles M. melisii and M. occidii in having five pairs of barbed setae on idiosoma, but it is easily distinguished by its small size (♀µ 302, ♂µ 318), by the length of idiosomal setae (see table 4), by the presence of barbs (from 4 to 6) only on the apical half of d1 setae in ♀and by the lenght of tibia IV seta (long two times the width of the same tibia). Referring to sorne preliminar observations, Melisia genus could be considered belonging to Canestriniidae phylogenic line and removed from Aëroglyphini Zakhv. Finally sorne biological and ecological features of the genus are discussed.