Fig. 6. Movements of the hind coxo-trochanteral joints of Aphrophora viewed posteriorly. The joint was moved from the fully levated position (A) through a partially depressed position (B) to the fully depressed position (C). Both the ventral and dorsal pivots of the joint are indicated by the blue arrows and are joined by the blue lines. The shorter blue lines indicate the insertions of the trochanteral depressor muscles. (D) Plot of the effective lever arms of the trochanteral levator and depressor muscles expressed as perpendicular distances between their insertion points and the axis of the pivot of the coxo-trochanteral joint over the full angular range of coxo-trochanteral joint movements.