(WJACTV.com)Necessity is the mother of invention, as someone famous and ancient once said, and Plato would be right in the case of a convenience store clerk faced with a would-be robber. She says she didn’t know if the woman demanding money from the register was armed, but darned if she wasn’t going to arm herself… with a can of bug killer. With limited options, the Pennsylvania clerk says she chose Raid wasp and bee killer after a woman dressed all in black with a mask over her face walked into the store late Sunday night. “That’s a heads up anyway,” she deadpanned to WJACTV.com about the mask.