I. sistens prefers open habitat such as tussock grasslands, dunes and braided rivers.

This species was originally described by Achille Guenée in 1868 using specimens collected by Richard William Fereday in the Canterbury region and named Eumichtis sistens.

long, elongate, smooth, ochreous; numerous longitudinal stripes, pale fuscous; sixteen legs.

The ♀ is slightly paler; its abdomen very thick, beneath with two lateral series of black markings.

[2] It can be distinguished from I. virescens as I. sistens is smaller, has a shorter and thicker forewing, with the outer edge being more rounded, and with less of a shine to the colour.

[2] This species prefers open habitats such as tussock grasslands, dunes and braided rivers.

The larvae of this species feed on grasses in the family Poaceae including grasses in the genera Rytidosperma and Elymus, and species including Poa cita and Agrostis capillaris.