The wingspan is about 12.5 mm for males and 13–17.5 mm for females. This species is similar in appearance to I. metadelta but lacks the areas of golden-orange spine like scales on its forewings. It is also similar to I. mira but the ranges of these two species do not overlap nor does I. minimira have the sharply pointed vertex nor the white terminal bands on the abdominal segments of I. mira. Also I. minimira is noticeablysmaller in size.
Little is known of the biology of this species and larvae are unknown. The adult moths are on the wing late in the season from January through to April. The females of this species are attracted to light but it appears the males are less so.