NO. 6 



GRASSHOPPER ABDOMEN — SNODGRASS 



17 



margin of the tympanal capsule of the first abdominal segment, to 

 which it is attached dorsal to the spiracle. This is the only thoracico- 

 abdominal muscle in the grasshopper. 



141. Longitudinal dorsal muscles (fig. 8). — A broad sheet of mus- 

 cles above the tympanal capsule, arising anteriorly on the first tergum 

 somewhat behind the base of the phragma, inserted posteriorly on the 

 anterior margin of the second tergum. 



142a, 142b. Lateral oblique dorsal muscles (fig. 9 A). — Two small 

 muscles arising laterally on the first tergum external to the longitudi- 

 nals, extending ventrally and posteriorly, close to the tympanal capsule, 



14-1 



ast 145 143 



154 156 172 



187 202 204 



Fig. 8.- — Muscles of the right side of the first five abdominal segments of 

 Dissosteira Carolina, male, together with the dorsal muscles {112) of the meta- 

 thorax. (See fig. 10 A for identification of muscles.) 



to their insertions behind the latter on the anterior margin of the 

 second tergum. 



14s. Median internal ventral muscle (fig. 8). — A wide band of 

 intersternal fibers over the lateral half of the sternal surface, arising 

 anteriorly on the antecosta of the first sternum, inserted posteriorly on 

 the anterior margin of the second sternum. 



144. Lateral internal ventral muscle (fig. 8) . — A cylindrical muscle 

 arising laterally on the antecosta of the first sternum, inserted pos- 

 teriorly on the anterior end of the apodeme of the second sternum. 



145. External ventral muscle (figs. 8, 9). — This muscle is a sternal 

 protractor. It takes its origin laterally on the posterior part of the 



