A model of a mite (top) shows the oblique furrow that Leendert van der Hammen thought was a “waist,” or the division between prosoma (the limb-bearing region at the front) and opisthosoma (the limbless region at the back). The image of a Micropsammus sp. mite (bottom), however, has a vertical furrow that looks a lot like a waist. (Image by Sameul Bolton, Ph.D.)