NO. O INSECT ABDOMEN SNODGRASS 57 



The ovipositor of the cricket consists of a small basal part, attached 

 to the ninth abdominal segment (fig. 14 B), and of a long, slender 

 shaft terminating in a sharp-pointed enlargement (fig. 17 B). The 

 shaft is formed of the first and third valvulae (figs. 17 A, E, 18, iVl, 

 3VI), which are respectively ventral and dorsal in position relative 

 to each other. The second valvulae are reduced to a pair of small, 

 membranous lobes (figs. 17 E, G, 18, 2VI) arising from the venter 

 of the ninth segment between the bases of the dorsal valvulae. The 

 base of the ovipositor consists of the first and second valvifers (figs. 

 14 C, 17 A, iVlf, 2Vlf), and the anterior and posterior intervalvulae 

 (fig. 17H, aiv, piv). The two valvifers on each side are closely as- 

 sociated with the lovv-er edge of the ninth tergum, but their true seg- 

 mental relations are shown by the origins of their dorsal muscles (fig. 

 17 E), those of the first valvifer (j) arising on the eighth tergum, 

 those of the second valvifer {6, 7) on the ninth tergum. The connec- 

 tion of the first valvifers with the ninth tergum is evidently a secondary 

 association, since it is clearly an adaptation to the special mechanism 

 of the orthopteroid type of ovipositor. 



The first valvifer is an irregularly triangular plate (fig. 17 A, F, 

 iVlf). Its only connection with the eighth segment is by the pleural 

 membrane uniting the eighth tergum and sternum ; otherwise its 

 associations are entirely with the ninth segment, except for its mus- 

 culature. By a strongly developed condyle near the middle of its 

 dorsal margin (F, a), the first valvifer freely articulates with the 

 lower extremity of the antecosta {Ac) of the ninth tergum. Its an- 

 terior end is produced into a tapering process {e) for the attachment 

 of muscles. At its posterior angle it has a narrow, flexible external 

 connection with the second valvifer {A, b), internal to which is a 

 deep notch (F, d) by which the first valvifer articulates with a con- 

 dylar surface (G, h) of the second valvifer (figs. 17 H, 21, dh). Ven- 

 trally the first valvifer is continuous by a narrow, flexible tongue (fig. 

 17 A, F, c) with the first, or ventral, valvula {iVl). From the inner 

 face of the first valvifer, above the inner articulation with the second 

 valvifer, there arises a large flat apodeme (F, H, /), giving attach- 

 ment to a thick, cylindrical muscle (E, H, p) from a median apodeme 

 {k) of the posterior intervalvula (piv). 



The second valvifer (fig. 17 A, G, 2Vlf) is of a more irregular 

 shape than the first, and its ventral part is directly continuous into 

 the third, or dorsal, valvula (3VI). Its posterior end, just before the 

 base of the valvula, is produced upward in a broad dorsal arm (G, i), 

 which terminates in an apodeme, the superior apophysis, projecting 

 within the ninth tergum (A, i). The anterior extremity of the second 



