How do butterflies mate?

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)