72 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



(GC) into which opens the spermatheca (Spt). The genital chamber 

 of the roach, however, has the appearance of being a mere pocket in 

 the anterior wall of the large vestibulum (Vst) lying above the seventh 

 sternum {VI IS) and the terminal lobes of the latter (VIISL). The 

 accessory glands (AcGl) open into the dorsal wall of the vestibular 

 chamber in the region of the ninth venter. The female genital invagi- 

 nations in the mantids and roaches, therefore, are of the type of struc- 

 ture shown diagrammatically at C of figure 8. 



The ovipositor has many points of resemblance in the Mantidae, 

 Blattidae, and Termitidae ; it is of small size as compared with the 



VIIIT KT 

 / y XT 



VIS 



vnistn 



Fig. 23. — Diagrammatic median section through the distal abdominal seg- 

 ments of Blatta orientalis. 



Note large vestibulum {Vst) formed within lobes of seventh sternum 

 (VIISL), concealing small genital chamber (GC) at its anterior end above 

 invaginated eighth sternum (VlllStn), gonopore (Gpr) and spermatheca! pore 

 (Spr) in walls of genital chamber, and accessory glands (AcGl) opening into 

 vestibule. 



usual ovipositor of other orthopteroid insects, and in some respects 

 it appears to be degenerate, while at the same time, especially in the 

 Blattidae, it shows unusual specializations that obscure the generalized 

 structure of the organ. 



The visceral region of the abdomen has a simpler mechanism in the 

 Mantidae and Blattidae than in the Tettigoniidae and Gryllidae, al- 

 lowing much less play between the dorsal and ventral plates. The 

 spiracles are contained in deflected marginal sclerites (fig. 16 B, Sp), 

 which belong to the dorsum and are therefore paratergites (pt), and 

 not " pleurites " as they are sometimes called. 



