The tendinous guide loop has three arms--proximal femoral, distal femoral, and fibular; the proximal and distal femoral arms unite posterior to the tendon of M. extensor iliofibularis; the proximal arm is medial to, and the distal arm is lateral to, the latter; the fibular arm joins the distal edge of the distal arm lateral to the tendon of M. extensor iliofibularis. The proximal arm extends anteroproximally lateral to the medial head of M. flexor perforatus digiti IV and medial to M. vastus lateralis pars postica, attaching to a narrow line on the anterolateral surface of the femur a short distance proximal to the external condyle and adjacent (posterior) to the origin of M. vastus lateralis pars postica. The distal arm extends anteriorly medial to the posterior head of M. flexor perforans et perforatus digiti II and medial to M. vastus lateralis pars postica, attaching in common with the tendon of origin of M. gastrocnemius pars externa to a small oval area on the posterolateral surface of the femur a short distance proximal to the fibular groove; the arm is also fused to the underlying articular capsule. The fibular arm (broadest of the three) passes deep to, and fused with, the common tendon of origin of the lateral heads of Mm. flexor perforatus digiti IV and flexor perforatus digiti II, superficial to the common tendon of origin of the anterolateral heads of Mm. flexor perforatus digiti IV, flexor perforatus digiti II, and flexor perforatus digiti III, and deep to the tendon of M. ambiens, attaching broadly to a narrow line on the anterolateral surface of the proximal part of the fibula; the arm is also fused to the underlying articular capsule. INNERVATION.--A branch of the middle peroneal division of the sciatic nerve sends twigs to the deep surface of the anteroproximal part; the dorsal peroneal division of the sciatic nerve penetrates the deep surface of the proximal end. INDIVIDUAL VARIATION.--In some instances a variable number of twigs arises from the peroneal nerve near the middle of the thigh and enters the deep surface of the muscle. They are difficult to expose without breaking and may have been overlooked in some specimens. _T. cupido_ INDIVIDUAL VARIATION.--The same variation is found as in _T. pallidicinctus_ (see above). In one leg, the tendon of insertion bifurcates into proximal and distal arms before attaching. _P. p. jamesi_ DIFFERENCES FROM TYPICAL _T. pallidicinctus_.--It arises from the ventral rather than the ventromedial surface of the lateral iliac process (there is no ventromedial surface to this process). INDIVIDUAL VARIATION.--In nearly all of the legs, minute twigs to M. extensor iliofibularis come off the peroneal nerve near the middle of the thigh. The insertional tendon tends toward doubleness in two legs. =_M. Piriformis_= (M. gluteus medius et minimus), Figs. 16, 20H, I _T. pallidicinctus_