NO. 8 INSECT ABDOMEN — SNODGRASS 97 



pophyses, arising respectively from the first and second valvifers (A, 

 B, iVlf, 2Vlf). Tlie second valvulae are fused by their inner faces 

 (D) ; the first valvulae are freely movable on flanges of the shaft 

 formed by the united second valvulae, and their lower edges are 

 movably connected with each other. Between the four valvulae is a 

 closed channel (r) for the conduction of the eggs. A pair of elongate 

 lobes, the third valvulae (A, B, 5F/), arise at the distal ends of the 

 second valvifers, and enclose the distal part of the ovipositor. 



The proctiger consists of the tenth and eleventh segments. Ordin- 

 arily its tip only is visible projecting from beneath the rostrum of 

 the ninth tergum (fig. 30 A, Ptgr). When exposed (E) the proctiger 

 is seen to consist of a basal part representing the tenth segment, and 

 of a distal part representing the eleventh segment. The dorsum of 

 the tenth segment contains a narrow transverse tergal plate {XT), 

 which is continuous ventrally with the posterior angles of a long 

 sternal plate {XS). The anterior angles of the sternum are produced 

 into a pair of small apodemal processes, on each of which is inserted 

 a muscle {8) arising on the ninth tergum (fig. 34, 8). The small 

 eleventh segment consists of a dorsal and a ventral lobe, apparently 

 representing the epiproct (fig. 30 E, Eppt) and the fused paraprocts 

 (Papt) enclosing the anal opening (fig. 34, An). Between their bases 

 on each side is a small, hairy lobe, evidently the rudimentary cercus 

 (fig. 30 E, Cer). At the base of the ventral wall of the eleventh seg- 

 ment is a small sternal sclerite (figs. 30 E, 34, XIS). Upon it are 

 inserted short, longitudinal, intersegmental muscle fibers (fig. 34, 9) 

 from the anterior part of the tenth sternum. From the latter there 

 arise also on each side a group of fibers ( 10) that go to the terminal 

 part of the rectum (Red). 



The copulatory and egg-discharging apparatus. — The short seventh 

 sternum of the female cicada ends, as we have observed (fig. 30 A, 

 VIIS), in a free posterior margin, and if this subgenital plate is de- 

 pressed there is exposed above it a large open cavity (fig. 32 A, Vst) 

 extending forward into the anterior end of the sixth segment beneath 

 the base of the ovipositor. This cavity clearly corresponds with the 

 vestibulum of the cockroach (fig. 23, Vst), though the vestibular 

 space is much larger in the latter insect because of the posterior ex- 

 tension of the seventh sternum {VIISL). 



In the anterior wall of the vestibulum of the cicada is a wide, thick- 

 lipped opening (figs. 31 A, 32 A, a) that leads through a short passage 

 (fig. 32 A, h) into a large, strongly muscular pouch {GC). The 

 median oviduct {Ode) connects with the anterior wall of the pouch, 

 and the spermathecal sac {Spt) opens by a narrow neck (c) into the 



