Hunting Flies

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

What are you doing? she asked.

He responded, Hunting flies.

Killing any?  She asked

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

Intrigued, she asked: How can you tell them apart?

He responded, 3 were on a beer can…2 were on the phone.