These insects use a spermalege to deceive the male’s "horribly sharp little penis."
African bat bugs try to fool each other to avoid painful mating rituals. From the book Wicked Bugs:
…All species of bat bugs participate in a form of lovemaking called traumatic insemination, in which the male bypasses the female’s vagina altogether and pierces her abdomen with his horribly sharp little penis. The sperm goes straight into the bloodstream, where some of it makes its way to her reproductive organs and the rest is simply absorbed and eliminated.
This is not at all an agreeable arrangement for female bat bugs. In laboratories, colonies of bat bugs quickly go extinct because the females simply cannot escape the painful and destructive attentions of the males long enough to heal and safely give birth. To get around this problem, the female of one subspecies, the African Afrocimex constrictus, developed an entirely new receptacle called a spermalege that is designed to redirect the male’s repeated stabbings to one particular location in the abdomen where they can be more easily accommodated.
To further complicate matters, amorous males will also pierce the bodies of male bat bugs. The males, being even more displeased by this behavior than the females, have developed tougher versions of the spermalege in the hopes of protecting themselves against their sex-crazed brethren. This has worked so well that females have taken notice. They are beginning to copy the males, imitating the sturdier version of this false genitalia that the females invented in the first place. This extraordinary case of females-imitating-males-imitating-females has resulted in what one befuddled scientist called "a hotbed of deception" in the twisted world of bat bug romance.
– Listen to the story (or read one) on NPR’s Fresh Air from WHYY (20 minutes)>>
– The excerpt is from Wicked Bugs: The Louse That Conquered Napoleon’s Army & Other Diabolical Insects by Amy Stewart