Figure 2.

Percentage reflectance of UV markings and associated background. A modal northern specimen has a large highly UV reflective cheek marking (N-ch) and a small UV reflective first shoulder marking (N-sh) but with a midtrunk marking too small to record such that the area that it would have occupied has very low reflectance (N-tr). A modal southern specimen has a large highly UV reflective first shoulder (S-sh) and midtrunk marking (S-tr), and a nonreflective cheek (S-ch). Areas adjacent to the cheek (a), shoulder (b), and trunk (c) are also nonreflective (and may appear black to human vision) to give a sharp contrast between the UV reflective marking and its background.