Slightly idealized representations of three typical adult Lepidoptera (left to right: Lasiocampidae, Hepialidae, Gelechiidae) to illustrate the variables measured. The right side of the thoraces is represented as devoid of the scale cover to make more evident the limits of this tagma. The three drawings are scaled to the same forewing length. Linear measurements are indicated by bars and areas by a striped pattern. FWL = fore wing length, FWW = forewing width, FWA = forewing area, HWA = hind wing area, TL = thorax length, TW = thorax width, AL = abdomen length, AW = abdomen width.