Newsnight joke

A wife walks in the kitchen and sees her husband holding a fly swatter.

She asks him, “Why are you holding the fly swatter?”

The husband says, “I’m killin’ flys.”

She asks, “Well, have you killed any yet?”

He says, “Yep, three males and two females.”

The wife, puzzled, says, “How can you tell what sex they are?”

The husband replies “Well, three were on a beer can, and two were on the phone.”