The Australian lucanid genus Eucarteria Lea is placed in junior new synonym
y with Cacostomus Newman. The sister-taxon of Cacostomus is identified as C
asignetus Macleay, from South America. A new name, Casignetini, is given fo
r the tribe Pholidotini Kikuta, which is based on a junior homonym. A key i
s provided for the species of Cacostomus.