Male butterflies find females by sight, and use chemicals called pheromones at close range. If the female accepts the male, they couple end to end and may go on a short courtship flight. They may remain coupled for an hour or more, sometimes overnight. The male passes a sperm packet called a spermatorphore to the female. The sperm then fertilize each egg as it passes down the female's egg-laying tube.
Mating Leafwings (Hypna clytemnestra)