How to Tell the Sex of a Fly

…from David in Thorpe Willoughby (UK)

A woman walked into the kitchen to find her husband stalking around with a fly swatter

“What are you doing?” she asked.

“Hunting Flies” he responded.

“Oh! Killing any?” she asked.

“Yep, 3 males, 2 females,” he replied.

Intrigued, she asked, “How can you tell them apart?”

“3 were on Beer Cans and 2 were on the Phone!”