"That Sort of Thing" joke

Little Lucy was playing in the garden when she spotted two spiders mating.

"Daddy, what are those two spiders doing?"

"They're mating, Lucy" he replied.

"What do you call the spider on top, Daddy?" Lucy asked.

"Oh, that's a Daddy Longlegs."

Lucy asked, "Oh, so one's a Daddy Longlegs and the other one is a Mommy Longlegs?"

Daddy replied, "No, both of them are Daddy Longlegs."

Lucy thought for a moment, then took her foot and stamped them flat. "Well, we're not having THAT sort of thing in our garden!"