76 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



segments. The median sclerite bears the opening of the spermathecal 

 tubes (Spr) on a small projection from its anterior margin (fig. 23, 

 Spr) , suggestive of the spermathecal spout of Gryllus, similarly situ- 

 ated except that it is contained in a pouch of the genital chamber 

 (fig. 18, u).The eggs of Blatta must be fertilized in the genital 

 chamber, and then passed out between the processes of the ovipositor 

 into the vestibulum, where they are enclosed in the ootheca. The roof 

 of the vestibulum contains the basal parts of the ovipositor (fig. 24 C) , 

 between which is the median opening of the large accessory glands 

 (AcGlO). An account of the histological structure of these glands, 

 together with a study of their contents, is given by Bordas (1909), and 

 the formation of the ootheca in the vestibular chamber has been de- 

 scribed by Kadyi (1879). 



The morphology of the female genital segments of the Blattidae 

 as given above, and as interpreted by Miall and Denny ( 1886) , Walker 

 (1919), Ford (1923), Crampton (1929), and Imms (1930), is so 

 strictly in accord with that of the genital segments of other Orthoptera 

 that it is difficult to see why certain recent investigators have not ac- 

 ceded to it. Vogel (1925), Nel (1930), and Heberdey (1931), for 

 example, follow Bordas (1909), who accepted the statement of Pey- 

 toureau (1893) that " I'overture du vagin se trouve entre le septieme 

 et le huitieme " urosternites. Vogel, therefore, disposes of the sclerites 

 of the genital surface (fig. 24 C, a, b) surrounding the gonopore 

 (collectively termed the " vaginal plate ") as secondary sclerotizations 

 of the membrane between the seventh and eighth segments, and re- 

 gards the median plate in the dorsal wall of the genital chamber (d), 

 bearing the opening of the spermathecal ducts, or situated behind the 

 latter in some species, as the true eighth sternum. Nel (i'93o) adopts 

 the same idea, and as a consequence is forced to conclude that the 

 sperm receptacles of Blattidae, since they open on the " seventh " in- 

 tersternal membrane, are not homologous with the spermatheca of 

 other insects. In describing Blattella he says : " The common oviduct 

 is short and opens by means of the gonopore on a raised fold of the 

 floor of the genital cavity very near its anterior end. This raised fold 

 is due to a pocket of the genital cavity extending beneath the part 

 carrying the gonopore. The gonopore is thus on the reflexed inner 

 surface of the seventh sternum, the seventh intersternal or so-called 

 intersegmental membrane." Further, he says of the spermathecal 

 ducts that they open into a short dorsal groove on the fold carrying 

 the gonopore, and he then observes that the position of the sperma- 

 thecal openings, which are thus on the " seventh intersternal mem- 

 brane ", constitutes an " aberrant and secondary condition." When 



