The mature larva of the weevil species Orobitiscyanea (Linnaeus, 1758), one of only two Palaearctic members of the supertribe Orobitiditae, is re-described, while the pupa is described for the first time. The biology of this species was studied at two sites in Germany. It was reared from seed capsules of Violacanina L. (Violaceae), and feeding holes were observed on V.riviniana Rchb. Adults of Orobitiscyanea and O.nigrina Reitter, 1885, specialists of Viola, show a well-developed escape mechanism, to which contribute a smooth surface, a rounded, nearly spherical body shape, and a seed-imitating thanatosis behaviour. The molytine weevil Leiosomacribrum (Gyllenhal, 1834), the only other known weevil specialist of Viola in Europe, has a smooth surface, also, and is the most spherical species of the genus. The unique characters of the larva and pupa of Orobitiscyanea are discussed in regard to the systematic position of this taxon.
Keywords: Blacus; escape mechanism; life cycle; mimicry; parasitoid; thanatosis.
Rafał Gosik, Peter Sprick.