[1] It is endemic to and found throughout New Zealand,[3] although it appears to be scarce at inland sites of tussock grasslands.

Its colour is pale green, becoming dark brown in the centre as the enclosed embryo develops.

After about twelve days the larvae turn a pale green and after moulting, lateral and subdorsal lines begin to appear.

Palpi stout, obliquely ascending, not rising so high as the vertex; third joint conical, very minute, not more than one-eighth of the length of the second.

Fore wings varied with glaucous-cinereous and with blackish, the former hue forming an irregular and interrupted submarginal band, which extends along the costa in three streaks to the exterior border; some zigzag black lines; orbicular and reniform marks of the usual shape; the first bordered with pale cinereous; the second wholly pale cinereous; fringe with pale cinereous longitudinal streaks.

insignis is variable in appearance and as a result is difficult to distinguish from its close relatives I. skelloni and I.

[2] The dorsum of the forewings of some specimens of I. insignis often has a "distinct whitish suffusion" which is considered diagnostic.

[2] Although this species can be found in a variety of habitats throughout the country it is scarce or absent from inland sites of tussock grassland.

[7] The sex pheromones used by I. insignis consist of combinations of tetradecenyl and dodecenyl acetates or alcohols.