1919] Walker: Structure of Orthopteroid Insects 275 



in oviposition. Very frequently the inner valves are connected 

 from the base distad to a varying extent by a fold of integument, 

 which may be termed the intervalvular membrane (im). The 

 inner valvulee are generally chitinized laterally and these 

 hardened parts or rami (rm) are connected by a strengthening 

 bar or pons valvularum (p) across the membrane, or the entire 

 fold may be chitinized dorsally. In the former case it is some- 

 times convenient to distinguish proximal and distal portions 

 of the rami according to their position in relation to the pons. 

 Like the ventral valvulae, the dorsal and inner pair may be 

 largely or wholly membranous when functionally degenerate. 



Between the bases of the dorsal valvulae and often closely 

 connected or even fused with them, is a median sclerite, the 

 superior intervalvida (sv). It bears a median vertical apodeme 

 for the attachrrient of important muscles connected with the 

 movements of the ovipositor, and its outer surface is continuous 

 below with the upper surface of the intervalvular membrane. In 

 some forms, such as Mantis and Stagmomantis , the rami of the 

 inner valves may be fused with this plate. Another median 

 sclerite, the inferior intervalvida (iv), is found on the ventral 

 surface of the base of the intervalvular membrane. With 

 the inferior intervalvula the rami of the inner valvule 

 are frequently connected, as in the Tettigoniidae and Acrididae, 

 and they are always connected more or less closely with a strong 

 ventral process from the base of each dorsal valvula, which may 

 be termed the inferior apophysis (iap). A similar but usually 

 larger process, the superior apophysis (sap) projects forward 

 into the hasmocoele from the upper part of the base of the 

 valvula. Both pairs of apophyses serve for muscular attach- 

 ment. 



The dorsal and ventral valvule meet laterally at their 

 bases, where they are both joined by a small plate, of more or 

 less triangular form, the valvifer (Crampton)i^ (vf). This 

 sclerite represents the antero-lateral part of the ninth sternum 

 and its outer (upper) anterior angle is connected with an 

 apodeme in the form of a ridge following the constriction 

 between segments 8 and 9 (ap. 9, int. ap.). The ridge is gen- 

 erally continued along the front margin of the valvifer and also 

 often along the lateral margin (using these terms in a morpho- 



^' The "epimerite" of Lacaze-Duthiers. Ann. Sc. Xat., 3 serie, Zool., tome 

 17, pp. 207-251, Pis. 10. II, 12 (1852). 



