Presented work is a summary of many years' observations. The first stage larvae of: "B. alismatis, "B. nodulosus", "B. frivaldszkyi"' "B. lutulentus", "B. binodulus", and "B. robustus" are described and illustrated for the first time. The illustrations of the detailed chaetotaxy of the mature larvae of: "B. alismatis", "B. lutulentus", "B. subscarinatus", "B. nodulosus", and "B. frivaldszkyi" are provided. Information about ecology, life-cycle and distribution of mentioned species are collected and presented. Analysis of the morphological features of the preimaginal stages of "Bagous" species in terms of their use in taxonomic studies based on the morphology of adult insects and results of the analysis of their preimaginal stages is conducted. Also comparision of the morphological structure of the first and mature larval stage is presented. The phylogenetic origin and kinship between Bagoinae and other selected weevils' groups are also studied.