Cotana dubia is a moth in the Eupterotidae family. It was described by Bethune-Baker in 1904. It is found in New Guinea. The wingspan is about 72 mm for males and 41 mm for females. Both wings of the males are darkish red-brown, the forewings with a broad oblique median band and a very broad curved postmedian band of darker ground colour, the latter having a scalloped outer edge, adjoining which is a series of broad spear-head ochreous marks up to the termen. There is also a large round ochreous spot at the end of the cell and all the veins are distinctly ochreous. The hindwings are like the forewings, but without the cell spot. Females have pale buff forewings, but darker in the terminal area and with a waved purplish medial stripe. There is a curved indefinite mauve suffused line, edged