NO. 6 GRASSHOPPER ABDOMEN SNODGRASS 79 



forward as a hoodlike fold that meets the lobes of the eleventh seg- 

 ment, and is then reflected inward to form the posterior wall of the 

 genital chamber (fig. 26). The genital chamber and the contained 

 phallic organs are thus ordinarily entirely concealed beneath the tenth 

 and eleventh segments in front, and the pallial hood behind. If the 

 pallium is pulled back from the eleventh segment it is to be seen that 

 the epiphallus occupies an anterior pocket of the genital chamber 

 beneath the venter of the tenth segment, and that the aedeagus is con- 

 tained in a posterior pouch lined by the inflected fold of the pallium 

 {Pal'), which latter extends inward and ventrally to the base of the 

 ventral lobe of the aedeagus {vl). The floor of the genital chamber 

 laterally slopes downward from in front (fig. 25 A), where the epi- 

 phallus is seated upon it, to the base of the inner fold of the pallium, 

 but medially, between the epiphallus and the aedeagus, it presents a 

 broad, smooth, rounded surface (D), the posterior margin of which 

 forms the basal fold (A, D, hf) overlapping the proximal part of the 

 aedeagus. The epiphallus is a large irregular sclerite, consisting of 

 two lateral lobes (D, h, h) connected by an arched bridge {i) , and 

 provided with the usual hooked anterior processes (/) and broad, 

 strong posterior processes {k) having a vertical position. Just laterad 

 of the epiphallus, in the wall of the genital chamber, are to be seen 

 the small oval sclerites {g) that give insertion to the large retractor 

 muscles {261) from the lateral parts of the ninth abdominal tergum. 



The structure of the aedeagus is well shown in the protracted con- 

 dition (fig. 33 B), in which the organ projects dorsally from a basal 

 sheath formed of the everted pallium {Pal) and the basal fold {hf) 

 of the genital chamber floor. The two parts of the dorsal lobe of the 

 aedeagus (r, m) are quite distinct, the narrow distal part (r), ending 

 in the small apical processes {n, p), being exserted from between the 

 lobate lateral walls of the proximal part (m). The ventral aedeagal 

 lobe {vl) embraces the dorsal lobe posteriorly, and between the two 

 is a deep cavity into which opens the vertical slitlike phallotreme in 

 the posterior wall of the dorsal lobe. The aedeagal apodemes (D, 

 Apa) project downward and forward from the base of the dorsal 

 lobe beneath the basal fold (B, hf), and their proximal parts are united 

 by a wide zygoma (D, s) in the under side of the fold (B, s). 



The phallotreme is a deep cleft in the dorsal lobe of the aedeagus ; 

 in its lateral walls are the usual two pairs of sclerites (fig. 25 H, o, q) . 

 The sclerites of the dorsal (anterior) pair end in the meatus, where 

 they are united with each other by a transverse bridge {t) \n the dorsal 

 wall of the latter ; the ventral (posterior) sclerites are continuous by 

 narrow upcurved arms (s) with the lateral plates {n) of the en- 

 6 



