Male Tanaecia iapis has dark velvety black upperwings, the hindwings have a wide distal green-blue border that continues at the tips of the forewings. The undersides of the wings are pale light brown with a series of dark striae on the forewing cells, without white spots. Female butterfly has pale brown upperwings with a series of white, helmet-shaped spots, series of marginal spots on both fore and hind wings. On the underside there is an additional whitish stripe on the margin and post-discal on both wings.
Larva: Tanaecia iapis larvae are greenish in color with several small spots on their body, have ten pairs of protuberances extending each instar development, these protuberances are projected horizontally and are always pressed onto the leaf surface, branching off with secondary spines arranged neatly around the spine. Its back has a white patch that appears between the 3rd to 10th ridges, these white patches merge and look like an eye.
Pupa: The Tanaecia iapis pupa is green with a series of golden spots arranged symmetrically, the body surface is smooth, the shape is sharp at each end, has two golden cephalic horns.