The treehoppers’ helmet is hard to justify from a selectionist standpoint. Schlepping it around adds a considerable energy burden, so it ought to do something important. What might be its useful function? Courtship, the usual suspect when it comes to exaggerated features, is eliminated by the absence of sexual dimorphism. Helmets are equally distributed in both genders; one can distinguish males and females only by their genitalia. Aerodynamics, another possible function, defies common sense. While some helmets are streamlined, others are decidedly not. And, in any case, the extra weight is detrimental to flying. Camouflage is a stronger bet but also problematic. Even in cases where the helmet’s form or colors fit the environment, a helmetless insect with the same colors and an otherwise identical form would be better equipped for hiding, being half the size or smaller. In the absence of smaller mimics, it is reasonable to infer that the helmet is not an antipredator tool.