82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



comprise the muscles normal to the trochanter, which are a levator 

 and a depressor arising in the coxa (fig. 44, 0, Q), and also special 

 depressor muscles (F) that have their origin in various parts of the 

 body segment carrying the leg. The basal lip of the trochanter usually 

 projects into the coxa well beyond the line of the coxo-trochanteral 

 hinge, thereby giving a strong leverage to the depressor muscles in- 

 serted upon it. 



The branches of the trochanteral depressor arising within the body 

 segment vary much in different insects and in different segments of 



Fig. 44. — Diagram of the mechanism of the hind leg of a grasshopper. 



O, levator muscle of trochanter, or extensor of telopodite, origin in coxa; 

 P, body branch of depressor of trochanter, or flexor of telopodite, origin on 

 tergum ; O, coxal branch of depressor of trochanter; S, levator of tibia; T, de- 

 pressor of tibia; U, levator of tarsus; V, depressor of tarsus; X, X, tibial 

 branches of retractor of claws ; x, tendinous apodeme of retractor of claws aris- 

 ing on base of unguitractor plate. 



the same insect. In the prothorax of Dissosteira there are three body 

 branches of the trochanteral depressor, one arising on the episternum 

 (fig. 33 B, yih), the second on the pleural arm (C, 71c), and the 

 third on the tergum (B, yid). In the mesothorax there are two 

 body branches of the muscle, both arising on the tergum. In the 

 metathorax a long outer branch and an inner branch (fig. 38 A, 133c) 

 arise on the tergum, and a short branch takes its origin on the under 

 surface of the lateral arm of the metasternal apophysis (fig. 38 A, E, 

 133d). These muscles ordinarily serve to lift the body on the legs, 

 but those of the hind legs of the grasshopper are probably accessory 

 to the extensor muscles of the tibiae in the act of leaping (fig. 44, P). 

 Muscles of the telopodite segments. — Since the trochantero- femoral 

 joint usually has but little movement in insects, the muscles of the 



