42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



first gonopods, but the bases of these appendages. Nel's studies were 

 made principally on Acrididae, in which the ovipositor differs in many 

 respects from that of other Orthoptera, and it is hence possible that 

 his interpretation applies only to this family. His statement concern- 

 ing the Odonata is based on the observation of George (1929) that 

 there is an inner lobe developed from each of the ovipositor processes 

 on the eighth segment of Agrion, which Nel would interpret as being 

 the true gonapophyses of the first gonopods, though George, himself, 

 makes no suggestion that they are other than secondary outgrowths. 



While, in general, there is no dispute concerning the ontogenetic 

 development of the first valvulae, the origin of the basal plates, or 

 first valvifers, in connection with them has not been so definitely ob- 

 served, and, as already noted, these sclerites have been variously 

 ascribed to the eighth and ninth segments. An examination of a 

 nymphal cicada in the last instar shows quite clearly that the genital 

 processes of the eighth segment (fig. 11 A, iGon) arise from a broad 

 plate {VIII LB) lying behind the gonopore {Gpr) and the small true 

 eighth sternum (JlllSln). This plate bearing the first gonapophyses, 

 which is incompletely divided into lateral halves, can scarcely be 

 anything else than the limb bases of the first gonopods united with 

 each other behind the eighth sternum. It is, on the other hand, clearly 

 the nymphal representative of the first valvifers of the adult (fig. 31 A, 

 iVlf), though this identity could not be verified in the specimens 

 studied by the writer because the imaginal parts were already re- 

 tracted forward far in advance of the nymphal parts. 



The splitting of the primary genital processes of the ninth segment, 

 or the budding of inner lobes from their mesal surfaces, represents 

 the development of the second gonapophyses from the bases of the 

 second gonopods. The result is the formation of four processes on the 

 ninth segment (fig. 11 B). The outer processes (IX LB) are the true 

 limb bases, which in the adult are differentiated into the second valvi- 

 fers and their terminal lobes, or third valvulae (fig. 31 B, 2Vlf, 3VI) ; 

 the inner processes (fig. 11 B, 2Gon) are the second gonapophyses, or 

 the second valvulae of the adult (fig. 31 B, 2VI). The true ventral 

 region of the ninth segment lies between the limb bases, concealed by 

 the second gonapophyses. In some insects it contains remnants of 

 the ninth sternum forming intervalvular sclerites. 



There is not much evidence from ontogeny as to the nature of the 

 distal lobes, or " third valvulae ", borne by the second valvifers in 

 the higher insects, but the development of the ovipositor as described 

 by Walker (1919) and others in Blattidae and by Crampton (1927) in 

 Gryllohlatta appears to show conclusively that the third valvulae 



