An awfully smelly insect

In Science we're doing a unit on insects and today we were talking about butterflies. So the lesson is going along nicely. The students are actually listening and not goofing off for a change. As we move on to discuss the life cycle of a butterfly I simply write the word "butterfly" on the board, or so I thought. As I walk away from the board after jotting down the final letter my students go back to their normal giggling and talking out. Frustrated, I ask them to quiet down when one brave girl raises her hand and says "Mr. Ritchason, I think you made a mistake." She points to the board and I immediately realize I had forgotten two very important letters. Instead of butterfly I had written the ever popular insect known as the butt fly. I'd better be careful to not leave off the first two letters when we discuss the grasshopper next week.