Segmentation of 4 pairts of legs of phytoseiid mites is composed of "coxa (基節)", "trochanter (転節)", "femur (腿節)", "genu (膝節)", "tibia (脛節)", "tarsus (ふ節)". The tarsus is divided into "basitarsus (基ふ節)" and "telotarsus (末ふ節)".
Segments of legs has several setae, normally hairy shape. But particular segments of legs has setae with abnormal shape. The abnormal setae are larger and/or longer than normal setae. The tip of the abnormal setae is shaped like a knot, spatula, or blunt. So the abnormal setae are called "macrosetae (巨大毛)", but its definition is ambiguous. The characteristic macrosetae are key to species identification.