There are four species of purple crow butterflies in Taiwan: Euploea mulciber, Euploea eunice, Euploea sylvester, and Euploea tulliolus. Every year after March, they will return gradually in groups to their breeding sites northward to reproduce. By using MJ as a drawing tool, it presents the ecological characteristics of the purple butterfly freeway lane with a simple watercolor style, which fuses reality and fiction.