To the knowledge of the herbivorous scolytid genus Thamnurgus Eichhoff (Coleoptera,Scolytidae)

Based on the male genitalia structure, 3 subgenera are distinguished in the genus Thamnurgus: Thamnurgus s. str. (type species Thamnurgus euphorbiae Küster; the subgenus includes also Th. characiae and Th. varipes), Parathamnurgus subgen. n. (type species Thamnurgus caucasicus Reitter; includes also Th. armeniacus, Th. kaltenbachii, Th. brylinskyi, and Th. pegani) and Macrothamnurgus subgen. n. (type species Thamnurgus delphinii Rosenhauer; includes also Th. petzi and Th. rossicus). Thamnurgus s. str. comprises species with the aedeagus lacking supporting apical structures and with unbranched apophyses. In the two other subgenera the aedeagal apophyses are branched and the apical supporting structures are differently arranged. Species of Thamnurgus s. str. are associated exclusively with Euphorbiaceae, species of Macrothamnurgus, with Ranunculaceae, and those of Parathamnurgus, with plants of several families. A key to Palaearctic Thamnurgus species based on the external and genital characters is proposed. The host plants and distribution of some species are clarified. In the aedeagus structure, the Palaearctic Thamnurgus species clearly differ from the African Thamnurgus and also from the members of Taphronurgus, Cynanchophagus, Triotemnus, and Xylocleptes. Data on the male genital structure support generic distinctness of Thamnurgus, Taphronurgus and Xylocleptes. Lectotypes of Th. armeniacus Reitter, 1897, Th. brylinskyi Reitter, 1889, Th. characiae Rosenhauer, 1878, Th. declivis Reitter, 1897, Th. delphinii (Rosenhauer, 1856), Th. pegani Eggers, 1933, and Th. petzi Reitter, 1901 are designated. Thamnurgus jemeniae Schedl, 1975 is transferred to Xylocleptes, and Th. orientalis Schedl, 1978, to Pseudothamnurgus. Based on the endophallus characters, Thamnurgus ugandensis Nunberg, 1961 and Th. lobeliae Eggers, 1939 are considered to belong to a genus distinct from the Palaearctic Thamnurgus.