In the paper, we observed the morphological characteristics of all stages of Parapoynx crisonalis (Walker, 1859) on Ttapa natans in details in the laboratory. The results showed that, its eggs were spherical, and the color was deeper in the middle. The young larvae were pale green, and the mature larvae were yellow. Except for the lst-instar larvae, the other larvae had tracheal gills. Its pupa was wrapped in silk cocoon. The adult had filiform antennae, an...