64 SMITHSONIAN MISCELLANEOUS COLLECTIONS \OL. 94 



The lateral walls of the proximal part of the dorsal aedeagal lobe 

 (fig. 24 B, 111) are usually strongly sclerotized and are often produced 

 dorsally in a pair of rounded lobes. The lateral sclerotizations are 

 continued anteriorly into a pair of large aedeagal apodemes (Apa) 

 invaginated in deep lateral pockets beneath the basal fold (A, B, bf) 

 that arches over the base of the aedeagus. Within the dorsal part of 

 this fold, in the wall of its ventral lamella, the bases of the apodemes 

 are solidly united with each other by a strong, transverse sclerotic 

 bridge, or zygoma (B, s). The aedeagal apodemes are the " enda- 

 pophyses " of Walker (1922), and the zygoma the "arch of the 

 endapophyses." The aedeagal apodemes give attachment to muscles 

 inserted on the walls of the endophallus. 



The ventral lobe of the aedeagus has the form of a broad trough- 

 like fold (fig. 24 A, id), usually membranous though sometimes more 

 or less sclerotized, extending upward from the floor of the genital 

 chamber at the base of the inner fold of the pallium {Pal'), and 

 closely embracing the base of the dorsal lobe of the aedeagus. It thus 

 conceals the lower part of the phallotreme. The ventral aedeagal lobe 

 is termed the " subventral lobe" by Walker (1922). 



The most highly developed and characteristic feature of the acridid 

 phallic apparatus is a large endophallic structure deeply invaginated 

 from the phallotreme into the ventral part of the ninth abdominal 

 segment (fig. 24 A, C, Enph). The walls of the endophallus are 

 covered by broad plaques of muscle fibers, which give the structure 

 the appearance of a strong muscular bulb (fig. 25 C, E, F). It is 

 necessary to remove these muscles in order to study the skeletal details 

 of the endophallus as presented in the following descriptions. 



The long, vertical, slitlike phallotreme opens directly into a laterally 

 compressed cavity of the dorsal lobe of the aedeagus. At the base 

 of the latter this open cleft passes into a short tubular meatus, which 

 leads into a large inner chamber of the endophallus. In each lateral 

 wall of the phallotreme cleft are two elongate parallel sclerites (fig. 

 24 C, o, q), from the outer ends of which project the external apical 

 processes {n, p) . The dorsal (anterior) sclerites (o) end proximally 

 in the meatus, where they are connected with each other by a strong 

 transverse arch {t) in the dorsal wall of the passage. The ventral 

 (posterior) sclerites ((/) extend proximally beyond the dorsal sclerites 

 a short distance, where they become much narrowed, and then each 

 makes an abrupt sigmoid flexure {s) dorsally in the lateral wall of 

 the meatus, beyond which it expands anteriorly as a large plate (m) 

 in the lateral wall of the endophallic chamber. The anterior end of 

 each lateral endophallic plate is produced beyond the lumen of the 



