Differences of macrosetae abundance within thoracic chaetotaxy zones A, L, M, Pm, and Pl for Th. 2 (top) and Th. 3 (bottom): A E. assuta with the lowest number of macrosetae B E. atrocincta with a moderate number of macrosetae C E. unostrigata with a moderate number of macrosetae D E. decemfasciata with the most macrosetae. Marked differences in zone Pm for both segments clearly differentiate between some groups of Entomobrya. Scale bars = 100 µm.