My wife walked into the kitchen to find me stalking around with a fly swatter. "What are you doing?" She asked. "Hunting Flies" I responded. "Oh. Killing any?" She asked. "Yep, 3 males, 2 Females," I replied. Intrigued, she asked. "How can you tell them apart?" I responded, "3 were on a beer can, 2 were on the phone."