Abstract
In butterflies, male wings are said to be more conspicuous or occasionally more brilliant than those of females (Darwin, 1874). However, the males of Narathura bazalus distributed from the Himalayas to Japan appear to have mostly black wings, whereas females possess a conspicuous blue mark on the forewing. This species, along with two related species N. japonica and Panchala ganesa, was examined for possible reflection of UV light. Specimens were photographed in UV light and also analyzed by spectrophotometry. N. bazalus males clearly reflected UV light from the whole dorsal surface of the fore- and hindwings, and sexual difference in dorsal colors was large in N. bazalus and small in N. japonica with no difference in P. ganesa.
