30 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



NOL. 94 



286. Dorsal dilator of the rectum. — A group of slender fibers aris- 

 ing dorsally on the tenth tergum mesad of the other muscles (fig. 14), 

 spreading fanwise ventrally to their insertions laterodorsally on the 

 posterior part of the rectum (fig. 16 A). 



287. Depressor of the cercus (figs. 7 D, 14).- — A narrow muscle 

 arising anteriorly on the median part of the tenth tergum, inserted 

 posteriori}- on the posterior margin of the median basal lobe of the 

 cercus. 



288. Median levator of the cercus (figs. 7 D. 14 ). — A broad muscle 

 arising anteriorly on the tenth tergum laterad of 287, inserted pos- 

 teriorly on the small sclerite between the tenth tergum and the basal 



Fig. 14. — Dorsal muscles of eighth, ninth, tenth, and eleventh abdominal seg- 

 ments of female of Dissostcira Carolina, ventral view. 



lobe of the cercus, some of the mesal fibers in some cases inserted on 

 the basal angle of the epiproct. 



28p. Lateral levator of the cercus (figs. 7 D, 14). — A slender mus- 

 cle taking its origin on the tenth tergum immediately laterad of 288, 

 inserted posteriorly in the membrane behind the tenth tergum close 

 to the outer angle of the base of the cercus. 



2^0. Lateral dilator of the rectum. — A fan of fibers arising an- 

 teriorly on the lateral part of the tenth tergum (fig. 14, 2po), spread- 

 ing mesad in a horizontal plane to their insertions along the lateral 

 line of the posterior part of the rectum (fig. 16 A). 



2pi. Ventral muscle of the paraproct (fig. 14). — A broad muscle 

 arising on the anterior margin of the lateral part of the tenth tergum, 

 inserted posteriorly on the base of the paraproct ventrally. 



