Costelytra zealandica (commonly known as the grass grub) is a species of scarab beetle found in forested areas of greater Wellington.[1] It was originally described in 1846 by the British entomologist Adam White as Rhisotrogus zealandicus from a specimen obtained during the Ross expedition.[2] The species is known to feed on roots of plants and trees, so is considered a pest for many farm pastures.
Prior to 2016, the New Zealand grass grub was mischaracterized as C. zealandica. In 2016 Coca-Abia and Romero-Samper found differences in syntype specimens between White's (1846) C. zealandica and Given's (1952) description and revised the species name of the latter to Costelytra giveni after Given.[3]