Fig. 3.

Walking on the oiled plate. (A) A tethered cockroach walked in place on a lightly oiled glass plate in view of two synchronized cameras (500 frames s^–1). (B) Ventral view of a cockroach. The colored dots on the legs show the points that were marked with paint and then tracked in the movies. The black arrows (bottom, right) indicate the coordinate system used, with the z-axis extending into the page. The x- and y-vectors shown would be ∼1 cm in length. (C) Position of points and angles measured. CTr, coxa–trochanter (joint); FTi, femur–tibia; ThC, thorax–coxa; TiTa, tibia–tarsus; TrF, trochanter–femur.