The Hawaiian endemic genus Labrocerus Sharp is redefined. The genera Argocerus Sharp and Eocerus Sharp are placed in synonymy with Labrocerus. L. vestitus Sharp is assigned as the type of the genus. Three species are described as new: L. auratus, L. producens, and L. argyroxiphii. L. simplex Sharp is placed in synonymy with L. concolor Sharp; L. affinis Sharp and L. pallipes Sharp are placed in synonymy with L. setosus Sharp; L. flavicornis Sharp is placed in synonymy with L. vestitus Sharp; and Argocerus subguttatus Sharp is placed in synonymy with L. similaris (Sharp). Lectotypes are assigned for L. moerens Sharp, and L. dasytoides Sharp. Comments are offered on 4 described species for which inadequate information is available for redescription. Keys are provided to the species by island.