Don't know what Praying Mantis mating equipment is like. Not all the mated males lose their heads. And then there's this.
https://www.abc.net.au/science/articles/2006/05/03/1629673.htm?site=science%2Ftalkingscience%26topic%3Dlatest
and then this
The female Neotrogla mounts the male, which is already a departure from the usual MO of animal sex. She then penetrates him with a gynosome, which is very similar to a penis, especially because the membrane that composes it hardens before she does this. The cringe-inducing part is next: this gynosome is so long that it pierces the male’s abdomen. That’s not all. It has hooks at the end that attach to pouches inside the male’s body, so the two are quite literally fastened together. The male then transfers his sperm to a duct inside his body, and she finishes the job by harvesting it into her own body. Scientists think that the pouches inside the male’s abdomens developed over time as a way to reduce the pain of the process
https://www.giantfreakinrobot.com/sci/move-praying-mantis-bug-sex-weirder.html
https://www.abc.net.au/science/articles/2006/05/03/1629673.htm?site=science%2Ftalkingscience%26topic%3Dlatest
and then this
The female Neotrogla mounts the male, which is already a departure from the usual MO of animal sex. She then penetrates him with a gynosome, which is very similar to a penis, especially because the membrane that composes it hardens before she does this. The cringe-inducing part is next: this gynosome is so long that it pierces the male’s abdomen. That’s not all. It has hooks at the end that attach to pouches inside the male’s body, so the two are quite literally fastened together. The male then transfers his sperm to a duct inside his body, and she finishes the job by harvesting it into her own body. Scientists think that the pouches inside the male’s abdomens developed over time as a way to reduce the pain of the process
https://www.giantfreakinrobot.com/sci/move-praying-mantis-bug-sex-weirder.html