Fig. 1. Anatomy of a Manduca proleg. (A) A late 5th instar larva is illustrated from the right-hand side. Prolegs are found on abdominal segments 3-6 (A3-A6). The specialized legs on the most posterior segments are called claspers. (B) A single right-hand side proleg is illustrated in a three-quarter frontal view and is representative of each proleg on body segments A3-A6. The pseudo segments, subcoxa and coxa are named by analogy with segments in the articulated thoracic legs. The tip of the proleg is called the planta and it carries the curved cuticular hooks (crochets) used for gripping. The principal and accessory planta retractor muscles (PPRM and APRM, respectively) have their origin on the lateral body wall near the spiracle (not illustrated) and insert at the planta and coxa-subcoxa boundary, respectively. The medial hairs are located along the inner surface of the proleg.