A morphological study of traumatic insemination in the genera Auchenacantha, a parasite of Dermoptera, and Passalurus, a parasite of Rabbits, revealed that the same phenomenon appeared twice in distinct lineages. In the Auchenacantha, adult females are inseminated in the vagina vera modified into a spermatic pouch. In the Passalurus insemination occurs in the ventral hypodermal field. Adult males probably mate with the female larval, stage four.