Redescriptions of last instar larvae of Ischyronota conicicollis (Weise, 1890) and Ischyronota desertorum (Gebler, 1833) (Coleoptera: Chrysomelidae: Cassidinae)

Abstract

Last instar larvae of Ischyronota conicicollis (Weise, 1890) and Ischyronota desertorum (Gebler, 1833) are redescribed and figured in detail using light microscope as well as SEM images. Larvae of Ischyronota are distinct within the tribe Cassidini and differ from those of the other genera in body not flattened dorso-ventrally, in thorax lacking scoli and in possessing abdomen with very short or completely reduced lateral scoli. The reduction of lateral scoli of body is probably correlated with feeding on succulent plants of saline habitat (Chenopodiaceae). Detailed examination showed that bodies of immatures of both species are covered with cauliflower-shaped sensilla, while pointed setae are only found on the middle of thoracic and first three abdominal sternites. Perhaps this character is also correlated with living in steppes and semi-deserts areas. Examination also showed that larvae of I. desertorum posses one-segmented maxillary palpi. This character has diagnostic value for I. desertorum and is unique within Cassidinae, which usually have two-segmented maxillary palpi.