he cognition of the species Stylosomus flavus Marseul, 1875 (Coleoptera, Chrysomelidae, Cryptocephalinae) from the South of Russia and the Northern Caucasus

The article provides an overview of the species Stylosomus flavus Marseul, 1875 in southern Russia and describes its forms. The first form, typical and similar to the nominative subspecies, has yellow elytra with a darkened suture. The second form, identified as a separate color variation from the southeastern region of the European part of Russia, differs from the typical form with light elytral sutures and basal segments of leg joints, as well as the apical edge of the aedeagus. The third form is a mountain form named f. teberdensis, found in the North Caucasus (Republic of Karachay-Cherkessia). It differs from the typical form with denser punctation on the pronotum, shorter setae on the pronotum, and darker coloration of the body. The predominant colour of this form is brown, whereas the typical form is yellow. The spermatheca of this form is almost symmetrical, while in the typical form one of the parts is broader. This form develops on Myricaria bracteata Royle, unlike the typical form, which develops in the Pre-Caucasus region on species of the genus Tamarix L.