Smithsonian miscellaneous collections . adult, arise directly from a median sclerotizationof the ventral wall of the segment, at the sides of which is a pair ofsmall but conspicuous oval lateral sclerites (x). There is thus no ster-nal plate in the ninth segment distinct from the bases of the valvulae. The two primary pairs of valvular processes increase in length withsuccessive instars (fig. 21 E), and the rudimentary second valvulaeappear ventrally between the bases of the third valvulae (F, iF/),but the relations of the valvulae to their respective segmental areasremain unaltered. Up to a l
Smithsonian miscellaneous collections . adult, arise directly from a median sclerotizationof the ventral wall of the segment, at the sides of which is a pair ofsmall but conspicuous oval lateral sclerites (x). There is thus no ster-nal plate in the ninth segment distinct from the bases of the valvulae. The two primary pairs of valvular processes increase in length withsuccessive instars (fig. 21 E), and the rudimentary second valvulaeappear ventrally between the bases of the third valvulae (F, iF/),but the relations of the valvulae to their respective segmental areasremain unaltered. Up to a late stage there is no evidence of the pres-ence of valvifers, except for the small lateral sclerites (x) of the ninthsegment, which increase in size and become more dorsal in posi-tion (F). 50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 In the last nymphal stage of the cricket, as illustrated in Gryllus(fig. 21 G), the valvifers appear as weak sclerotizations in the areaspreviously membranous laterad of the bases of the valvulae. The. H ^;: I ~r K Fig. 21.—Development of the ovipositor of Gryllidae and Tettigoniidae. A, ventral view of end of abdomen of very young nymph of Nemobuis. B,seventh and eighth sterna of Nemobius at later stage. C, ninth and postgenitalsegments of same. D, end of abdomen and ovipositor of young nymph ofNcoconocephalus. E, late instar nymph of Nemobius. F, same, lower part ofninth segment and valvulae. G, lower parts of genital segments with base ofovipositor of last nymphal instar of GryHtis, showing origin of first valvifer inpodial area of eighth segment. H, base of ovipositor of adult Gryllus , same of Orocharis saltator. J, same of Neoxabia bipiinctata. K, same ofCyrfoxipha coluinbiaiia. first valvifer (iVlf) lies in the ample membrane of the eighth seg-ment behind the small eighth sternum. Ventrally it is connected withthe base of the first valvula (iVl), and posteriorly it is prolonged asa prominent lobe (y) inserted between the ba
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