Silver Fern Looper

Hudson described the larva of this species as follows:

Prior to its last moult, it is pale green, with white sub-dorsal and lateral lines and conspicuous brown blotches on the sides of each segment, often meeting across the back. The full-grown larva is about 1-inch in length, stout, slightly attenuated towards the head; dull green mottled with white with the edges of the segments yellowish-brown; there are two conspicuous white sub-dorsal lines and two broad irregular white lateral lines, narrower at the segmental divisions; the spiracles are brown.

Meyrick described the adult male of this species as follows:

♂. 37mm. Head, palpi, thorax, abdomen, and legs pale ochreous, back of crown and anterior part of thorax darker; face whitish-tinged; palpi 2+1⁄4; abdomen and legs thinly sprinkled with dark fuscous. Antenntae whitish-ochreous, pectinations 12, apical 1⁄6 simple. …

C. aristarcha is endemic to New Zealand. It is found throughout the North Island. D. E. Gaskin pointed out in 1966 that although Hudson regarded it as common in Wellington he had yet to collect it there. He was of the opinion that the range of this species had contracted as cultivation of land increased.

The larva feed during spring, are very sluggish and can observed on the silvery underside of its host plant. C. aristarcha pupates on the ground under its host plant and amongst leaf detritus and moss. It stays in that state for approximately 6 weeks. Adult moths are on the wing from October until April but can sometimes also be seen during the winter months. Gaskin believed there were two broods but was unsure at which life stage C. aristarcha passed winter as both adults and larvae are present in spring. Adults of this species have been collected by beating its host plant and have been observed in the evening at Metrosideros perforata when in flower. They are attracted to light.