EN
The first and last instars of Isturgia roraria (Fabricius, 1777) caterpillars are described and illustrated in details. The mouthparts, antennae and thoracic legs are used for the first time for the description within the genus Isturgia (Hübner, 1823). The description and complete illustration of thoracic leg of adult larva with numeration and nomenclature of all pores and setae are included. Some important characters of intermediate larval instars are recorded. New morphological details of pupa are presented.