This fly seems to be toying with something in its legs — but it’s actually holding its own head. This doesn’t happen on purpose. As an insect, a fly has an exoskeleton, and its head is attached to its body by only a thin, flexible chitin membrane, similar to a balloon twisted onto a bottle opening. Flies are extremely clean creatures and spend much of their time grooming. When cleaning their heads and eyes, they lift their front legs and brush rapidly. If they use too much force, the fragile con