1925] Evternal Anatomy of Head and Abdomen of the Roach 211 
vestigators, such as Chopard, consider that the vagina opens 
between the seventh and eighth sternites, and in a footnote, 
Peytourea refers to the observations of Miall and Denny, 1893 
on the development of the region in question, in a passage which 
may be roughly translated as follows: “The delicate indurated 
membrane which leads out to the vaginal opening is not the 
eighth sternite, but arises as a fold of the intersegmental 
membrane.” If this is true, it would seem to indicate that the 
peri vulva is a thickening of the intersegmental membrane, rather 
than a sclerite of the eighth abdominal sternum. 
The sclerites immediately behind the plates labelled vs in Figs. 
20, 19, 17, etc., may represent the structures called the basival- 
vulse in other Ortho pteroid insects by Crampton, 1917, and 
Walker, 1919. As may be seen in Fig. 19 the plates vs are 
sclerites of the eighth uromere, and they are connected with the 
bases of the ovipositor valves vv. A small transverse ventral 
sclerite ms situated between the sclerites vs of Fig. 20, is con- 
sidered to be the ninth sternite by Miall and Denny, 1886, 
although it is not quite clear how they arrived at this con- 
clusion. Its posterior portion surrounds the thecapore tp of 
Fig. 20, or opening of the spermatheca, in which spermatozoa 
are stored up at the time of mating, to fertilize the eggs. Hence 
the opening of the spermatheca tp of Fig. 20 is normally situated 
immediately above the vulva vid (out of which the eggs pass) 
when the parts are not unnaturally separated as in Fig. 20. Dr. 
Walker, however, informs me that this supposed spermatheca 
is really a gland. The sclerite labelled ms in Fig. 17 re- 
presents the internal view of the sclerite labelled ms in Fig. 20, 
showing the internal projections of the plate in question. 
The ovipositor of the roach is composed of three pairs of val- 
vulse. Of these, the dorsal valvulse dv and inner valvulse iv (Figs. 
20, 17, 19, etc.) belong to the ninth uromere, while the ventral 
valvulse vv belong to the eighth uromere. The dorsal valvulse 
dv have been variouly termed the posterior or third gonapophyses, 
dorso valvulse, sur valvulse, nono-valvulse, etc. The inner ones iv 
have been called the inner or second gonapophyses, intervalvulse, 
etc.; and the ventral valvulse have been called the anterior or 
first gonapophyses, octovalvulse, sub valvulse, ventro valvulse, etc. 
