Praeacrospila melanoproctis is a moth in the family Crambidae. It was described by George Hampson in 1899. It was described from São Paulo, Brazil,[1] but has also been recorded from Costa Rica[2] and Cuba.
The wingspan is about 34 mm. The forewings are ochreous with a fuscous costal area. There is a sinuous dark antemedial line with a small annulus in the cell beyond it, as well as a large ochreous-centered discocellular reniform dark patch with a waved postmedial line with a large dark apical patch beyond it. There are two small ochreous spots on its outer edge. The hindwings are ochreous with a discocellular speck, as well as an apical dark patch and a series of marginal specks.[3]