Systellus

The myrmecophilous brentid genus Systellus Kleine, 1917 (Eremoxenini) is redescribed. Amorphocephalus mentaweicus Senna, 1898 is transfened to the genus Systellus (new combination) and becomes a senior synonym of S. rex Kleine, 1917 (new synonymy) which is the type species of the genus. The systematic position of Systellus within the tribe Eremoxenini is briefly discussed. This genus is easily recognised by the antennae with nine segments instead of 11, but is close to Paramorphocephalus in most other character states. Systellus mentaweicus is recorded for the first time from Peninsular Malaysia and Thailand. In Malaysia several specimens Were found in a nest of the ant Camponotus (Tanaemyrmex) sp. This is the first host record for the genus Systellus. There are seven species in this myrmecophilous genus of Carabidae.