276 Annals Entomological Society of America [Vol. XII, 



logical sense), and near its lower end it is sometimes raised 

 into a prominent internal process (pap) for the attachment 

 of muscles. In the Acridoidea this process reaches an enormous 

 size, although the valvifer and ridge are greatly reduced or 

 absent. 



Distal Valvular Connections. 



The manner in which the valvulae are connected beyond the 

 base varies greatly, depending upon differences in the methods 

 of oviposition. As a rule the dorsal and ventral valvul£e form 

 a sheath enclosing the inner valvulae, the dorsal frequently 

 overlapping or roofing oyer both ventral and inner valvulae. 

 Very frequently the inner and ventral valvulae fit together 

 more or less firmly by a tongue-and-groove joint extending 

 along their adjacent outer edges for the greater part of their 

 length, and in some cases (most Tettigoniidae) such a joint 

 also occurs between the dorsal and ventral valvulae. In both 

 cases the ventral valvulae bear the groove or grooves, the 

 other valvulae the tongues. Where such connections exist 

 the only possible movements of the valvulae in relation to one 

 another are sliding movements backwards and forwards. 

 These are best seen in the Tettigoniidae and doubtless also 

 occur in Grylloblatta. In the Gryllidae, in which the inner 

 valvulae are vestigial, the dorsal and ventral pair are immovably 

 united with one another at the apices and no movement takes 

 place between them. In the Acrididffi, Acrydiidae and Tri- 

 dactylidae (Ripipteryx), on the other hand, the dorsal and 

 ventral valvulae are free beyond their bases, and can be moved 

 in the sagittal plane like a pair of forceps, of which the dorsal 

 pair form one of the jaws, the ventral pair the other. In the 

 Phasmoidea, Mantoidea and Blattoidea, the valvule are more 

 or less flexible and apparently not functional in the forms 

 studied. There is no close connection between them beyond 

 the base, although there is usually an ineffective tongue-and- 

 groove engagement between the inner and ventral valvulae. 



Development of the Ovipositor. 



The first indication of the ovipositor (Fig. 9) is generally 

 a pair of tubercles on the ninth sternum, sometimes on the hind 

 margin, but more frequently farther forward. These are soon 

 followed by two other pairs, one from the hind margin of the 

 eighth sternum, or just behind it, the other from the ninth 



