[1][2] This species is endemic to New Zealand and can be found in the South Island, although not in the Nelson, Dunedin or Southland regions.

This species was first described by George Howes in 1946 using 10 specimens collected at Homer and named Aletia nobilia.

[4] In 1950 George Hudson, in his book Fragments of New Zealand entomology, also discussed this species under this name.

Subterminal line slightly deeper in colour than main wing surface and narrowly edged outwardly with ochreous.

Cilia white, with light brown-grey bars between vein endings in males; grey, with a grey-white basal line in females.

[2] The blueish-grey sheen on the forewings of this species mimics the colour of the rocks found in the habitat it prefers.

[2] Physetica caerulea can also possibly be confused with I. nobilia however the former is much smaller and has a pale yellowish shade to its underside.