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?'

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

H/T Ted Foster