NO. 2 THORACIC MUSCLES OF THE COCKROACH — CARBONELL I5 



/jj. Sternal muscle of the coxa (fig. 25). — From the end of the 

 sternal arm to the ridge which Hmits the meron on the anterior 

 (ventral) wall of the coxa. Acts probably as a rotator. 



757. Spinal muscle of the coxa (figs. 25, 30). — Long, fiat muscle, 

 originates on second spina, goes to the ridge which limits the 

 meron on the anterior (ventral) wall of the coxa. Acts probably 

 as a rotator. 



755. Main depressor of the leg (figs. 22 to 28). — The most power- 

 ful muscle of the leg and mesothorax. Originates on several 

 parts of mesothorax and coxa ; its branches converge to a broad 

 apodeme inserted on the proximal angle of the trochanter. 



a. Tergal branch (figs. 22 to 26). — Origin on antero-lateral 

 part of the tergum, 



b. Sternal branch (fig. 26). — Origin on downward-bent flange 

 of the anterior edge of the sternal arm. 



c. Basalar muscle of the fore zving (fig. 27), — This large 

 bundle of fibers is attached anteriorly to an apodemal tendon 

 arising from the anterior edge of the basalar plate (fig. 33, 

 Ba) (edge which articulates with the edge of the epi- 

 sternum), inserts posteriorly on the broadest portion of the 

 trochanteral tendon. Corresponds to the pronator-extensor 

 of the fore wing in other insects. 



d. Coxal branch (fig. 26). — Origin on mesal part of coxal wall. 



e. Coxal branch (fig. 28). Origin on the anterior part of coxal 

 rim, near coxo-trochantinal articulation. 



1^6. Posterior coxal depressor of the leg (fig. 25). — Broad muscle 

 which originates on the posterior (dorsal) wall of the coxa, near 

 the rim. Its fibers converge to apodeme attached to the tro- 

 chanter. 



757. Anterior coxal depressor of the leg (figs. 2y, 28, 30). — Arises 

 from the mesal part and mesal angle of the coxa, its fibers con- 

 verge on apodemal tendon attached to the proximal end of 

 trochanter. 



1^8. Anterior coxal levator of the leg (fig. 30). — Slender, weak mus- 

 cle, from the anterior wall of the coxa to a thin apodemal tendon 

 attached to the femoral part of the trochanter. 



759. Main coxal levator of the leg (figs. 25 to 28). — With several 

 origins on the coxal wall, its fibers converge on apodemal ten- 

 don attached to the trochanter. 



a. (figs. 25, 26). — Has its origin on the posterior wall of the 

 coxa, toward the meral angle. 



