The eyes of the winged males and larviform, wingless females of the firefly Rhagophthalmus ohbai differ from each other in several respects. Compared with the eyes of the males, those of the females contain fewer (35 versus ca. 3500) and smaller ($20{mu}m$ versus $24-31{mu}m$) facets and anatomically they are of the apposition type. Their main function appears to be to detect light intensity changes from day to nighttime; resolving power of the female eye must be poor and e-vector discrimination would be absent. The eyes of the males consist of a smaller, dorsal region of ca. 500 ommatidia of about $250{mu}m$ length and a larger, ventral region of ca. 2000 ommatidia of about $640{mu}m$ length. The microvilli of the dorsal eye region are somewhat wider than those of the ventral region (55 nm versus 45 nm) and are less regularly arranged. A tapetal reflecting layer is only present in the dorsal eye region. The small clear-zone between dioptric apparatus and retina in the dorsal eye region would not allow as good a superposition image to be produced as in the ventral eye region with its 5 times wider clear-zone. The regular orientations of the microvilli in the rhabdoms and the lack of a proper tapetum in the ventral eye region suggest that e-vector discrimination should be possible.