This species is similar looking to I. panda but I. falsidica has dark dashes on their hind-wings.

This species can be found open high country and has been seen flying during the day in sunny warm weather.

[1] In 1913 George Hampson also described the same species, using specimens including the lectotype male that was collected in the Tararua Range, and named it Hyssia hamiltoni.

[5] In 2019 Robert Hoare undertook a major review of New Zealand Noctuidae.

Forewings rather elongate-triangular, apex obtuse, termen slightly waved, obliquely rounded; fuscous-grey, mostly overlaid with white suffusion; subbasal line cloudy, dark fuscous, not reaching dorsum; first and second lines indistinctly margined with dark-fuscous irroration, first slightly curved, second waved, strongly curved outwards on upper 2⁄3; median shade of dark-fuscous irroration, bent near costa; orbicular-suboval, whitish, edged laterally with dark fuscous; reniform whitish, lower third fuscous-grey edged with whitish : anterior edge of subterminail line formed by a waved shade of dark-fuscous irroration.

[1] I. falsidica is similar in appearance to I. panda but the former usually has dark dashes along the hind-wings.