Abstract
A description of the larva of Drusus plicatus Radovanović is given for the first time. The most important diagnostic characters enabling separation from larvae of the other Drusinae from the southeast Europe are listed. Molecular, ecological, and ethological features and distribution patterns of the species are given. Additionally, information on the sympatric caddisfly species of the three springs where larvae and adults of Drusus plicatus were found and presented.