SMITHSONIAN MISCELLANEOUS COLLECTIONS 



\0L. 94 



attached anteriorly on the latter, and posteriorly on the dorsal margin 

 of the base of the dorsal valvula. 



2^2. Depressor of the ventral valvula (fig. 17 A, B). — A massive 

 bundle of fibers arising on the ventral face of the apodeme of the 

 ovipositor, inserted on the basal plates of the ventral valvula. This 

 muscle possibly corresponds with the intersternal protractors, or 

 external ventrals, of the pregenital segments. 



2-/^. Adductors of the ventral valvulae (fig. 17 C, D). — A pair of 

 flat muscles arising anteriorly on the proximal parts of the inner 

 margins of the apodemes of the ovipositor, the two converging pos- 

 teriorly to the median apodeme of the ventral intervalvula (/). The 

 retraction of the intervalvula causes an adduction of the valvulae. 



Fig. 13. — Laterodorsal and ventral muscles of the seventh and eighth segments 

 of the female abdomen of Dissosteira Carolina, right side, inner view. 



2/4. Adductors of the dorsal valvulae (fig. 17 A, B, C). — Origin 

 on the proximal part of the dorsal surface of the ovipositor apodemes, 

 insertion posteriorly on the posterior intervalvula (B, C, piv). The 

 contraction of the convergent muscles of this pair approximates the 

 valvulae of opposite sides. 



2/j. Muscle of the second valvula (fig. 17 B, C). — A small muscle 

 arising laterally on the dorsal surface of the anterior intervalvula, in- 

 serted posteriorly in the distal end of the small second valvula. 



2/6. Dilator of the spermathecal aperture. — A very small muscle 

 of a few delicate fibers arising on the lateral basal plate of the ventral 

 valvula (fig. 17 E, a), inserted mesally on the side of the groove in the 

 dorsal wall of the genital chamber containing the aperture of the 

 spermathecal duct (fig. 20 D). 



