40 SMITHSONIAN' MISCIlLLANEOUS COr,LF.CTIONS VOL. 94 



of each dorsal valvula is prolonged anteriorly in a strong ventral ramus 

 (D, ra), the expanded base of which (g) is firmly hinged to the dorsal 

 lip of the exposed base (li) of the lateral apodeme of the same side. 

 The apodemal bases, therefore, are the fulcral points for the move- 

 ments of the dorsal valvulae. The ventral valvulae, on the other hand, 

 have their fulcra of movement on the strongly protruding articular 

 ridges (/) on the bases of the dorsal valvulae. The dorsal valvulae 

 are united between their bases by a membranous integument containing 

 the anterior intervalvula (D, aiv), the bases of the second valvulae 

 {2VI), and the posterior intervalvula (B, C, piv). 



The second, or intermediate, valvulae (fig. 17 A. B, D, 2]!) are 

 short lobes projecting from the membrane between the ventral rami 

 of the dorsal valvulae. The two are adnate mesally for most of their 

 length, but their sclerotic lateral and terminal parts form free lobes en- 

 closing a trough-like depression between them (D). The united bases 

 of the second valvulae are supported on a median process of the an- 

 terior intervalvula (aiv). 



The intervalvulae are small sclerites lying between the bases of the 

 dorsal valvulae, where, because of the position of the latter, they 

 become dorsal and ventral relative to each other. The ventral anterior 

 intervalvula (fig. 17 D, aiv) is a transverse sclerite bridging the space 

 between the anterior ends of the ventral rami of the third valvulae, 

 and giving support by a median process to the united bases of the 

 second valvulae. Just before the transverse sclerite is a small, oval, 

 median sclerite (/) bearing a short slender apodeme (e) on which are 

 attached the muscles of the anterior intervalvula. The posterior inter- 

 valvula is a small hexagonal plate lying dorsally between the bases of 

 the third valvulae (B, C, piv). 



A characteristic feature of the acridid ovipositor is the presence of 

 the pair of long, flat, lateral apodemes (fig. 17 D, Ap) extending 

 forward from the angles between the bases of the dorsal and ventral 

 valvulae. These apodemes are well developed also in Tetrigidae and 

 Tridactylidae, but they have no apparent homologues in the ovipositor 

 of other insects. They give attachment to the levator and depressor 

 muscles of the valvulae, to the muscles of the posterior intervalvulae, 

 and to the ventral dilators of the rectum, while the proctractor muscles 

 of the ovipositor are inserted on their anterior ends. 



The stalk of each apodeme is hollow, and its base appears as the 

 strongly sclerotic lips of a transverse cleft in the angle between the 

 bases of the dorsal and ventral valvulae, where, as already observed, 

 the ventral ramus of the dorsal valvula is hinged to the dorsal lip of 

 the apodemal invagination. It might be supposed, therefore, that the 



