NO. 8 INSECT ABDOMEN SNODGRASS 99 



two cases is not identical, yet it is evident that the posterior opening 

 is a secondary one, and that it is located, as in Lepidoptera, at the 

 aperture of the accessory gland. 



The morphological nature of the genital pouch of the female cicada 

 is clear when it is considered that it lies above the eighth abdominal 

 sternum (fig. 32 B, VlllStn), and that both the gonopore {Gpr) 

 and the spermathecal pore (Spr) lie in its walls. The pouch can be 

 nothing else than the genital chamber (fig. 8 C, GC) greatly en- 

 larged and modified in an unusual manner. It corresponds exactly 

 with the genital chamber of the Orthoptera (figs. 19 B, 23, GC). 

 In the cicada the eighth sternum is mostly reflected forward upon the 

 floor of the genital chamber (fig. 32 B, VlllStn), but its morpho- 

 logically anterior end projects as a short fold beneath the entrance 

 of the chamber (A, VlllStn). The posterior part turned forward 

 is sclerotized as a small plate surrounding the base of the oviducal 

 cone. The gonopore of the cicada, therefore, lies morphologically in 

 the eighth sternum just as it does in the cockroach (figs. 23, 24 C, 

 Gpr). The relation of the terminal genital structures in Magicicada 

 to the more usual structure of these parts in other insects is shown 

 in the series of diagrams given in figure 8. 



The posterior opening of the genital chamber in Magicicada septen- 

 decim between the bases of the second valvulae is undoubtedly a 

 special modification to allow the eggs to be discharged directly into 

 the closed channel of the ovipositor. This condition is not peculiar 

 to the 17-year cicada; the same structure was long ago described in 

 Dundubia (Cicada) mannifera by Doyere (1837), but has received 

 little or no attention since, so far as the writer can find. Doyere 

 refers to the genital chamber as the " vestibule copulateur ", and 

 other writers have called it the " bursa copulatrix ". Holmgren 

 (1899) studied the female genital organs of various homopterous 

 forms (Cicadarien), now classed in the families Cercopidae, Cica- 

 dellidae, and Fulgoridae, but he says that all species examined by him 

 have but a single genital opening. Myers (1928) gives a review 

 of literature on the female reproductive organs of Cicadidae, in- 

 cluding Doyere's paper, and makes no mention of two openings. 

 He describes and figures the female organs of Carineta formosa, 

 but the terminal genital structures in this species must be quite dif- 

 ferent from those in Dundubia and Magicicada. The single open- 

 ing shown by Myers is at the point where the accessory glands with 

 yellow sacs open into the " oviduct ", and would therefore appear 

 to be the posterior opening of Magicicada. The writer has examined 

 specimens of several other species of Cicadidae, which, though too 



