Abstract: There are cornuti in the endophallus of Iampronadata cristata (Butler) unmated male moths. During the first mating of male moths. The cornuti were transferred to bursa copulatrix of female moths. The mating status of field-collected male and female moths can be determined by the use of cornuti, spermatophore, and the coexistent relations of cornuti and spermatophore. Based on the criteria, the mating status of L. cristata (Butler) in the oakery of Zijinshan Mountains was determined during 1990-1993.