ID SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



lateral muscle {^8p), both arising on the anterior margin of the tenth 

 tergum. The median muscle is inserted on a small sclerite in the 

 membrane behind the tenth tergum before the mesal lobe of the base 

 of the cercus (C, a) ; the lateral muscle is inserted in the same mem- 

 brane very close to the outer angle of the base of the cercus. A' third 

 muscle (D, 28y) arises anteriorly on the tenth tergum just mesad 

 of 288, and is inserted on the posterior margin of the basal lobe of 

 the cercus. This muscle is evidently a depressor of the cercus. The 

 fourth cereal muscle (D, 2pj) is an adductor. It arises mesally on 

 the anterior part of the epiproct (fig. 14) and is inserted on the ex- 

 tremity of the basal lobe of the cercus. Because of the oblique plane 

 of the cereal base this muscle produces an adduction of the appendage. 

 It is interesting to note that the cerci, which appear to be appendages 

 of the eleventh segment, have only one pair of muscles (-pj) taking 

 their origins in this segment, and that they have no muscular con- 

 nections with the paraprocts. 



II. THE ABDOMINAL MUSCULATURE 



The body muscles are well developed in the abdomen of the grass- 

 hopper, particularly in the male, and individual muscles are easily 

 identified. The several groups of muscles in the pregenital segments 

 conform with the classification of the abdominal muscles into dorsal 

 iiiuscles, ventral muscles, lateral muscles, transverse muscles, and 

 spiracular muscles as given by the writer in an earlier paper (Ab- 

 domen, Part I, Smithsonian Misc. Coll., vol. 85, no. 6, 1931). The 

 plan of musculature in the pregenital segments, however, is lost in the 

 genital and postgenital segments, and the muscles of these segments 

 must be studied separately. The series of numerals designating the 

 abdominal muscles follows that of the thorax of Dissosteira (Smith- 

 sonian Misc. Coll., vol. 82, no. 2, 1929). The transverse muscles are 

 omitted from the descriptions of the segmental musculature and are 

 treated as a separate topic. 



MUSCLES OF THE FIRST SEGMENT 



The musculature of the first abdominal segment is simpler than that 

 of the following segments because of the elimination of some of the 

 dorsal muscles and most of the lateral muscles. 



140. Lateral oblique intersegmental muscle (figs. 5 A, 9 A). — A 

 very slender muscle, observed only in the female, attached ventrally 

 on the apex of the lateral arm of the metasternal apophysis, extending 

 dorsally and posteriorly, mesad of the leg muscles, to the anterior 



