Miroculis (Ommaethus) Savage and Peters, 1983 (Ephemeroptera, Leptophlebiidae) is reviewed based on fresh material from Southeastern Brazil and on type specimens. Miroculis (Ommaethus) cipoensis sp. n. is described based on male and female imagos from Serra do Cipó, Minas Gerais State, Brazil. It can be distinguished from other species of the subgenus based on the following characteristics: forewings with membrane brown and dark brown mark around cross veins; hind wing uniformly brown; forceps segment I light brown, segment II and III lighter; penis lobe long (at least ⅔ of forceps segment I) and apically rounded and curved on apical ¼; length of body between 5.0 and 6.3 mm. Photographs of fresh material belonging to M. (O.) froehlichi Savage and Peters, 1983 and M. (O.) mourei Savage and Peters, 1983 are provided, clarifying the boundaries between the existing species of the subgenus. Based on that, M. (O.) misionensis Domínguez, 2007 is considered a junior synonym of M. (O.) mourei. A key to the male imagos of the subgenus is presented, as well as a distributional map with updated records of the species.