Izatha austera

Hudson described the larvae as follows:

Its length is slightly over 1⁄2 in.; slender and cylindrical; the head is reddish-brown, highly polished; the second segment dark brown and horny; the third segment has two triangular brown horny dorsal plates; the rest of the body dull ochreous, with a very broad slaty-black dorsal band and four conspicuous horny dorsal tubercles; the terminal segment is horny, yellowish-brown; there is a series of conspicuous lateral tubercles and a whitish lateral ridge; all the tubercles emit long yellowish-brown bristles. Meyrick described the adults of the species as follows:

Male. — 17-18 mm. Head, antennae, thorax, and abdomen dark fuscous. Palpi dark fuscous, second joint mixed with pale ochreous, terminal joint with a suffused pale ochreous band above and below middle. Legs dark fuscous, median ring of tibiae and apex of all joints whitish-ochreous. …

I. austera is endemic to New Zealand. This species is widespread throughout the North Island, with a single South Island record from north-west Nelson. This species is present in Northland, Auckland, Coromandel, Waikato, Bay of Plenty, Taranaki, Taupo, Gisborne, Hawkes Bay, Rangitikei, Wellington and Nelson districts.

Larvae live in silken tubes under the bark of dead branches of its host species. The larvae live during winter months and are mature by the end of September. Adults are on wing from December to February. This species have been collected via sugar traps or by beating shrubs during the daytime. I. austera only comes sparing to light. When resting on bare tree trunks the adult moth is very inconspicuous.