Females of <i>Mitophyllus arcuatus</i> Holloway and <i>M. irroratus</i> Parry are not readily separable by morphology (Coleoptera: Lucanidae)
The lucanid Mitophyllus arcuatus Holloway was recently described having been previously considered as a form of M. irroratus Parry. Males of M. arcuatus and M. irroratus can be readily separated by the shape of the mandibles but differences between females are more subtle. Mitophyllus females from Bay of Plenty kiwifruit orchards could not be separated into M. arcuatus and M. irroratus based on selected morphometrics (measurements of the mandible basal projection and the spermathecal duct) and on other traits in a key and notes by Holloway. Where no males are collected from the same locality, some caution is needed in assigning females to species.