82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



(B, pt) . The abdomen ends with the small tenth segment, or proctiger 

 (X), from beneath which project the wide third valvulae {3VI) with 

 the shaft of the ovipositor {Ovp) between them. 



The seventh segment is funnel-shaped, expanded posteriorly. Its 

 large sternum (fig. 26 A, VIIS) projects ventrally in a median lobe 

 beneath the base of the ovipositor, and its posterior margin is inflected 

 to form the ventral and lateral walls of a vestibulum concealing the 

 lower anterior parts of the eighth and ninth segments, and the base 

 of the ovipositor. 



The eighth segment is mostly concealed within the seventh (fig. 

 26 A). When removed from the latter (B) it is seen to consist of a 

 complete annulus, though the ventral part is reduced and membranous. 

 Dorsally the segment presents a tergal plate (VI I IT), with small 

 paratergal lobes (pt) containing the eighth spiracles; its lateral walls 

 are formed by large, triangular pleural plates, which are the first 

 valvifers (iVlf) ; the membranous ventral part forms a small fold 

 (VlllStn) at the base of the ovipositor, representing the rudimentary 

 eighth sternum. The genital opening appears to be situated above 

 the sternal fold between the bases of the first valvulae, but its existence 

 here could not be positively determined in the dried specimens 

 examined. 



It is of particular interest to note that the first valvifer (fig. 26 B, 

 iVlf) has a true pleural position on the side of its segment. Crampton 

 (1929) mistakes the valvifer of the eighth segment in Hemiptera 

 for a basivalvula, but the identity of the plate in question is shown 

 without doubt by its musculature, and by the fact that the first val- 

 vula is directly connected with its ventral angle (C). The first 

 valvula, however, has an inner ramus (D, rivli)' which curves upward 

 from its dorsal margin and is connected with a small plate (m) 

 attached to an extension (n) of the lower anterior margin of the 

 ninth tergum (IXT). This basal sclerite (m) of the inner ramus 

 of the first valvula might be regarded as a part of the valvula. inas- 

 much as it is continuous ventrally with the latter by a fold of the 

 connecting membrane, or it might be supposed to be a part of the 

 ninth tergum ; but it is more probable that it is a part of the ramus 

 itself, since there is inserted upon it a short thick muscle arising on 

 the inner face of the valvifer, which would appear to represent the 

 basal muscle of the gonapophysis in Thysanura (fig. 6 F, gmcl). In 

 any case, the structure of the first valvifer, and the inner connection 

 of the first valvula with the ninth tergum, as shown in Pentacora, 

 are features characteristic of all the Hemiptera. The movements 



