This species lives in a variety of habitats from open grasslands to clearings in forest and at a range of altitudes from the sea level to the alpine zone.

Larval host species include Juncus procera, Carex secta as well as on tussock grasses such as Poa cita, P. colensoi and Festuca novae-zelandiae.

[2] George Hudson described the larvae of I. semivittata as follows: The larva, which feeds on native grasses, is about 1+1⁄4 inches in length, subcylindrical, slightly tapering at each end; dull green, very finely streaked with reddish-brown; the dorsal and subdorsal lines are indicated by fine double reddish lines; there is a series of white dots, one on each segment, except on the second and last; the lateral line is very distinct, dark reddish-brown, shaded with cream colour below; the spiracles are blackish; the underside of the larva and the whole of the second segment is a paler and clearer green than the rest of the body.

[2] The similar species I. sulcana can be distinguished from I. semivittata as the former is much larger, has a darker hindwing and abdomen and has only on to three spots located behind the middle of the forewing in comparison to the 8 or 9 of I.

[2] This species lives in a variety of habitats from open grasslands to clearings in forest and at a range of altitudes from the sea level to the alpine zone.

[2] Larval host species include Juncus procera, Carex secta as well as on tussock grasses such as Poa cita, P. colensoi and Festuca novae-zelandiae.