46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



eighth abdominal sternum (fig. 20 A, GC). The anterior basivalvular 

 sclerites of the first valvulae extend into its dorsal wall (figs. 17 E, 

 20 A, C, c), and in a depression between them is situated the aperture 

 of the spermatheca (Spr). The opening of the median oviduct, or 

 gonopore, lies anteriorly in the floor of the genital chamber (fig. 20 A, 

 Gpr). A short distance before the spermathecal and oviducal aper- 

 tures the genital chamber ends as a blind pouch. Here, in Dissosteira, 

 a pair of muscles from the eighth sternum have their insertions on the 

 ends of the anterior basivalvular sclerites (fig. 17 E, 248). In Mela- 

 nopliis the anterior end of the genital chamber is provided with two 

 large lateral pockets (fig. 20 C, /), and the muscles {248), inserted on 

 the basivalvular sclerites (c) in Dissosteira, are attached in Melano- 

 pliis on the walls of the lateral pockets. Similar pockets of the genital 

 chamber in Anacridimn aegyptiiim are described as " vesicules ovi- 

 ductaires " by Varde (1929), who shows from a study of their his- 

 tology that the pouches are glandular structures in this species. 



The female genital chamber of insects generally is usually said to 

 be an invagination between the eighth and ninth abdominal sterna. 

 In the Acrididae, however, it is quite clearly an ingrowth between 

 the eighth sternum and the bases of the first gonopods, which are 

 located behind the sternum. This fact is noted by Nel (1929), who 

 observes that the genital chamber in the female of Colemania and 

 Locust ana is " formed at the hind margin of the eighth sternum by 

 the sternum overgrowing the bases of the anterior ovipositor lobes." 

 The basal sclerites of the first valvulae thus come to lie in the dorsal 

 wall of the genital chamber. 



The female gonopore of adult Acrididae, as above noted, is situated 

 on the floor of the genital chamber above the reflected posterior end 

 of the eighth abdominal sternum. It is an elongate median aperture 

 (figs. 4, 13, Gpr) between membranous folds that converge and unite 

 posteriorly on the dorsal surface of the base of the tgg guide. The 

 oviductus communis (figs. 13, 20 A, Ode) extends forward to the 

 seventh segment where it receives the lateral oviducts. The definitive 

 position of the female gonopore in Acrididae, it is claimed by Nel 

 (1929), is not the site of the primary invagination that gives rise to 

 the median oviduct. In late embryos of Locustana, Nel says, the 

 common oviduct first appears as an invagination of the conjunctival 

 membrane between the seventh and eighth segments (fig. 20 B, Ode'), 

 the aperture of which runs out as a groove on the venter of the eighth 

 segment. In this respect, therefore, the acridid appears to recapitulate 

 a more primitive condition permanently retained in Dermaptera. Dur- 

 ing the first nymphal stage of the grasshopper, as described by Nel, 



