Butterflies, my dear Mister tsuwm, gather around the clay banks of cool springs and creek banks. They seek the nutrients in the soil. Which happened to be same cool place that your less than cosmopolitan English-misspeaking ancestors kept their home-churned butter to keep it from spoiling.

Not trusting anyone they accused the pretty flies of stealing.
Today, you know better, but being a tsuwm, you still call them butter flies and your proof is in the yellow pudding that doesn't exist except in wild-eyed folklore and your dusty books.