{315}[Illustration: FIG. 191.—Development of ovipositor of _Locusta viridissima_: _a_, terminal segment; _a′_, cerci; _a″_, secondary division of terminal segment; _b_, penultimate (ninth) segment; _b′_, primary papillae of this segment; _b″_, secondary divisions thereof; _c_, eighth segment; _c′_, its papillae. (After Dewitz.) A, embryo ready for emergence; B, portion of integument of the ventral plates of eighth and ninth segments; C, the appendages in a condition somewhat more advanced than they are in A.] [Illustration: FIG. 192.—Structure of ovipositor of _Locusta viridissima_: A, arrangement of parts at base, _c′_ being separated and turned outwards; B, transverse section. The parts of the appendage bear the same lettering as in Fig. 191. (After Dewitz.)] Near to one another, on the middle of the ventral aspect of the true ninth abdominal segment, are seen the two papillae (_b′_), which at first are the only visible indications of the future ovipositor. If, however, the integument be taken off and carefully examined, it will be found that there exist on the eighth abdominal plate two spots, where there is a slight thickening and prominence of the integument (Fig. 191, B, _c_). From these two spots the two lower rods of the ovipositor are produced; these two, together with the two growths from the ninth segment, form the four external rods of the ovipositor. Inside these there exist in the completed structure two other rods (Fig. 192, B, _b'′_). These are produced by a growth from the inner parts of the two papillae of the ninth segment. The relations of the six rods in their early condition are shown in Fig. 191, C, where the two primary papillae _b′_ of the ninth segment are seen with their secondary offshoots _b″_; _c′_ being the papillae of the eighth segment. The subsequent relations of the pieces are shown in Fig. 192; A exhibiting the base of the organ with the lower rods turned on one side to show the others, the shaded parts indicating {316}muscular attachments; B is a transverse section of the organ. In these figures the different parts of the appendages bear the same lettering as they do in Fig. 191. It will be seen that in the completed structures the parts _c′_ have become very intimately connected with the parts _b′_ and _b″_, which belong to another segment.