Eurythecta robusta

Butler described the species as follows:

♂︎♀︎. Primaries sordid white, acute; a broad oblique patch beginning just within the base of the discoidal cell and terminating in a point near to the centre of inner margin, a slender subcostal dash near the base, five spots on the apical half of costa, a squamose patch across the median veins, and the terminations of the nervures black-brown; secondaries greyish, particularly towards the outer margin; body sordid white : primaries below grey, the costal margin white, crossed by greyish spots towards apex; secondaries paler grey, the costa white; body below white. Expanse of wings 4+1⁄2 lines.Meyrick noted that the species is extremely variable in colour.

E. robusta is endemic to New Zealand. The species has been found in North, Mid and South Canterbury. The type locality of this species is likely Yaldhurst/West Melton in Christchurch and this area is now largely modified by the development of lifestyle blocks. The species has occurred at Kaitorete Spit, Gore Bay, Porters Pass, McLeans Island, and has surviving populations at Ashburton, and at the mouths of the Rangitata and Hinds rivers. Hudson stated that the species had been collected at Alexandra and Ben Lomond but there is some doubt as to whether this is the case.

The females of E. robust are flightless. Adult males are on the wing from September until January.