My hand was going down on him when Jem spoke.
Jem was scowling. It was probably a part of the stage he was going through, and I wished he would hurry up and get through it. He was certainly never cruel to animals, but I had never known his charity to embrace the insect world.
“Why couldn’t I mash him?” I asked.
“Because they don’t bother you,” Jem answered in the darkness. He had turned out his reading light.
– Harper Lee
To Kill a Mockingbird, Chapter 25. Scout is about to squish a roly poly that found its way inside the house and Jem stops her. He equates the innocence of the bug with that of Tom Robinson and doesn’t want to see another innocent creature perish.