62 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 94 



Pal'). In the Tetrigidae the exposed dorsal part of the pallium forms 

 a long valvelike flap containing two elongate plates (fig. 2y A, B, 

 PlVlv). In Tettiffidea the plates are separated by a median mem- 

 branous line (B), but in Acrydium and Paratettix, according to 

 Walker (1922), the pallial valve is armed betv^^een the plates w^ith a 

 pair of bars terminating anteriorly in upcurved hooks. 



The male genital chamber of the Acrididae (fig. 24 A, GC) has 

 the usual relations of the male genital pouch to the ninth and tenth 



ixs A 



ejs Ki J-^ L>ej ejs C 



Fig. 24.- — Diagrams showing the general structure of the male genitalia of 

 Acrididae. 



A, vertical longitudinal section of end of male abdomen somewhat to left of 

 median plane, showing the organs contained in the genital chamber (GC), and 

 the endophallus (Enph) projecting into the body cavity. B, the aedeagus and 

 its basal apodemes. C, the aedeagus and endophallus. 



Aed, aedeagus; An, anus; Apa, aedeagal apodeme ; bf, basal fold; Dej, ductus 

 ejaculatorius ; dl, dorsal lobe of aedeagus; ejs, ejaculatory sac; Enph, endophal- 

 lus; Epph, epiphallus ; Eppf, epiproct; GC, genital chamber; IXS, sternum of 

 ninth abdominal segment; IXSL, genital lobe of ninth sternum; Pal, pallium; 

 Pal', inner fold of pallium; Papf, paraproct ; Phtr, pallotreme (external opening 

 of endophallus) ; Rcct, rectum ; sjys, spermatophore sac of endophallus ; vl, ventral 

 lobe of aedeagus; AT, tergum of tenth abdominal segment, X.F, venter of tenth 

 segment. (For alphabetical lettering see fig. 25.) 



abdominal segments — that is, it is an invagination cavity between 

 the end of the ninth sternum and the venter of the tenth segment. 

 Owing to the vertical position of the subgenital plate, however, and 

 the forward extension of the pallium from the latter, the opening of 

 the cavity is dorsal between the eleventh segment and the inflected 

 margin of the pallium. The anterior part of the genital chamber is 

 covered by the ventral walls of the tenth and eleventh segments, the 

 posterior part by the hood of the pallium. The floor of the chamber 

 usually slopes downward posteriorly from the venter of the tenth 

 segment (X.V) to the base of the inner pallial fold {Pal'). 



