Thudaca heterastis is a moth in the family Depressariidae.

The forewings are snow white with a moderate orange streak immediately beneath the costa from the base to the costa near the apex, sometimes obsolete beyond two-thirds.

There is a rather broad orange streak along the inner margin to the anal angle, becoming suddenly subdorsal on the basal fourth and not quite reaching the base, usually more or less wholly suffused with dark fuscous, posteriorly attenuated.

A straight orange streak, suffused with dark fuscous, is found from the costa near the apex to the anal angle, sometimes widely interrupted or visible at the extremities only.

The hindwings are pale whitish grey, faintly yellowish tinged.