64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



ings mixed with a gluey discharge from the pvipositor. As is the 

 usual habit with crickets, Gryllns deposits but one egg in each boring. 



The movements of the ovipositor made by Gryllus during egg 

 laying in soft soil are thus seen to be very simple ones, and there 

 is scarcely any accompanying motion of the abdomen, such as the 

 contortions made by Oecanthus while drilling into wood. The ovi- 

 positor of Gryllus is lowered preparatory to its insertion into the 

 ground, its penetration is accompanied by the rapid back-and-forth 

 movement of the valvulae on each other, and after withdrawal it is 

 elevated again to the usual position, The entire organ is probably 

 capable of a slight protraction and retraction. 



The fixed points of movement in the basal parts of the ovipositor 

 are the articulations of the first valvifers with the lower edges of the 

 ninth abdominal tergum (fig. 17 A, F, 21, a), the outer and inner 

 articulations of the two valvifers on each side with each other (fig. 

 17 A, b, fig. 21, dh), and the weak, flexible unions of the first val- 

 vulae with the lower angles of the first valvifers (c). Otherwise 

 the ovipositor has a free movement on the abdomen by means of its 

 membranous connections with the latter. 



The movements of depression and elevation of the ovipositor affect 

 not only the shaft but the entire basal parts of the organ, and the 

 fulcra are the articulations of the first valvifers with the lower angles 

 of the ninth tergum (figs. 17 A, 21, a). The muscles that accom- 

 plish these movements are clearly the anterior and posterior lateral 

 muscles of the ninth tergum (figs. 17 E, H, 21, 5, 8), the first of 

 which are inserted ventrally on the anterior intervalvula (aiv), the 

 second on or near the posterior intervalvula (piv). The insertion 

 points of these muscles are anterior and posterior to the articulations 

 of the first valvifers on the ninth tergum (a), and pulling upward 

 on these points correspondingly depresses or elevates the ovipositor. 

 Morphologically the levators and depressors of the ovipositor are the 

 tergosternal muscles of the ninth abdominal segment. 



The alternating opposite movements of the dorsal and ventral 

 valvulae on each other depend on the articulation of the first val- 

 vifers with the ninth tergum (fig. 21, a), and on the inner articula- 

 tion of the two valvifers of each side with each other (dh). A de- 

 pression of the posterior end of either of the first valvifers (B) 

 causes the corresponding ventral valvula, which is flexibly attached to 

 the ventral angle of the first valvifer, to slide proximally on the 

 lower edge of the dorsal valvula. But, since the first valvifer rocks on 

 the fulcrum (a) of the ninth tergum, its posterior end, when de- 

 pressed, describes a short arc of a circle in a downward direction 



