The lilypad forktail's body length varies from 0.9 to 1.3 inches. The name "forktail" comes from tiny projections off the tip of males' abdomens, which help to identify the species. The male's thorax is blue with broad black mid-dorsal and shoulder stripes and horizontal stripe on sides. The abdomen is mostly black with some blue near the tip. The males can be confused with the bluets. The female's thorax is similar to the male's except the pale areas are bright red. The abdomen is mostly black with a red tip. The red areas become pruinose blue-gray with age. The old females will be difficult to distinguish from other old female forktails.