Catharylla mayrabonillae is a moth of the Crambidae family. It is found in Panama, Costa Rica, Colombia, Venezuela, Guyana, Surinam, French Guiana, Ecuador, Peru and Brazil (Acre, Amazonas, Distritò Federal, Pará, Rondônia). The length of the forewings is 7.5–8.5 mm for males and 9.5–10.5 mm for females. The costal line on the forewings is ochreous or white in the basal half and white in the apical half. The median transverse line is ochreous and the subterminal transverse line is ochreous. The hindwings are white with a thin faded ochreous transverse subterminal line.