Imma acosma is a moth in the family Immidae. It was described by Alfred Jefferis Turner in 1900. It is found in Australia, where it has been recorded from Queensland and New South Wales.[1]
The wingspan is 16–17 mm. The forewings are brownish-fuscous, with the posterior portion of the disc sometimes suffused with brownish-ochreous and sometimes with a small fuscous erect line on the inner margin at one-fifth. A very irregularly angled fuscous line runs from the costa before the middle to the inner margin beyond the middle and there is a fuscous dot in the disc at two-thirds, followed by two oblique fuscous lines from the costa at three-fifths and four-fifths towards, but not reaching, the anal angle and hindmargin respectively. All these markings may be obsolete. Sometimes, there is a dark fuscous line close to the upper three-fourths of the hindmargin. The hindwings are fuscous-grey.[2]