Myrmidonistis is a genus of moths of the Crambidae family. It contains only one species, Myrmidonistis hoplora, which is found in Australia, where it has been recorded from Queensland. The wingspan is about 23 mm. The forewings are greenish-grey, irrorated with white. There is a white costal streak, margined beneath with fuscous-reddish. The remaining lines are very obscure, narrow and white. The hindwings have the same colour and mostly the same markings as the forewings.