Cotana dubia is a moth in the family Eupterotidae. It was described by George Thomas Bethune-Baker in 1904. It is found in New Guinea.[1]
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.[2] 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 obscurely with yellowish and with a fine very indistinct dark margin, beyond which is a row of dark dashes on each vein. There is also a subapical purplish wedge-shaped terminal patch. The hindwings are orange yellow, with a lunulate postmedial line, followed by a row of dark dashes on each vein.[3]