Cephalissa

Cephalissa is a monotypic moth genus in the family Geometridae. Its only species, Cephalissa siria, the orange triangle moth, is endemic to New Zealand. This species has been classified as nationally vulnerable by the Department of Conservation. It has suffered a contraction of its range, no longer being seen in Dunedin or Invercargill. It is currently found in the Mt Watkin Scenic Reserve, in eastern Otago, in the Rongahere Gorge and in the Dansey Ecological District. C. siria is known to inhabit kahikatea forest amongst Carex species as well as short tussock grasslands and shrubland. The larval host plant is Fuchsia perscandens. Adult moths are on the wing in October and November.

== Taxonomy == This genus and species were first described by Edward Meyrick in 1883 using specimens collected by Frederick Hutton in Dunedin. In 1884 Meyrick described both the genus and the species in greater detail. In 1898 George Vernon Hudson described and illustrated the species under the name Hydriomena siria. Hudson also used the same synonym when he described and illustrated the species in his 1928 publication. John S. Dugdale also discussed the species in 1971 and placed this species in the genus Hydriomena was in doubt. In 1988 Dugdale confirmed this placement. The lectotype specimen, collected in Dunedin, is held at the Natural History Museum, London.