This is apparently a common and generally distributed species. It has occurred plentifully at Wellington, Blenheim, Christchurch, and Rakaia.
The expansion of the wings is about 1½ inches. The fore-wings are dark grey crossed by four wavy, black-margined, transverse lines; beyond the outermost of these lines there is a black band running parallel with the termen, and beyond this again a broader band of the ground colour; the orbicular spot is very minute and dull white; the reniform, which is surrounded by a black shading, is large, yellow towards the costa, and white towards the termen. The hind-wings are dark grey. The females are generally much darker than the males, some specimens having the fore-wings very dark brownish-black.
Both sexes vary a good deal in the depth of colouring, but the markings appear to be quite constant.
The larva is dark brown, tinged with pink; the subdorsal region is paler, there are a series of diagonal blackish stripes on each segment, and the anterior portions of the larva are much darker than the rest of the body.
The specimens I reared were fed on lettuce, but I expect that the caterpillar feeds on low plants generally. It is full grown about January. The pupa state is spent in the earth.
The moth appears in January, February, and March. It is very common at the flowers of the white rata, and may also be attracted by sugar and by light.
ORTHOSIA IMMUNIS, Walk.
(Tæniocampa immunis, Walk., Noct. 430. Cerastis innocua, ib. 1710 (locality probably erroneous). Agrotis acetina, Feld., Reis. Nov. pl. cix. 6. Orthosia immunis, Meyr., Trans. N. Z. Inst. xix. 30.)
(Plate [V]., fig. 29.)
This species has occurred at Wellington in the North Island, and at Blenheim in the South Island.