1922] Walker: Structure of Orthopteroid Insects 33 



end of the genital cavity, and having a subvertical instead of a 

 horizontal position, due to the general upturning of the 

 extremity of the abdomen. 



Under the flattened paraprocts lies the pseudosternite, a 

 transverse, heavily chitinized plate of complex form (Fig. 52). 

 It is thus widely separated from the genital aperture, having a 

 position comparable to that of Ceuthophilus when the penis of 

 the latter is fully everted. 



Immediately in front of the extremity of the penis and 

 partly concealed by a membranous fold a strong transverse 

 arch (ar) may be seen, having a horizontal position. This bar 

 curves forward on each side, passing beneath the surface and 

 continuing far forward beneath the pseudosternite, with which 

 it is connected by strong muscles. The two arms of this arch, 

 from their muscular connections, appear to represent the 

 endapophyses, but have lost their connections with the pseudo- 

 sternite, the proximal part of the rami being absent. Con- 

 nected with the arch is a pair of chitinized lobes (ra) flanking 

 the penis and meeting caudad in the median line. From their 

 muscular connections, as determined by Miss Norma Ford, 

 who is now engaged in a comparative study of the abdominal 

 muscles of Orthopterous insects, these lobes appear to represent 

 the distal parts of 'the rami. There is also a pair of conical 

 elevations arising from the penis roof, where it passes into the 

 rami. These are not structures of morphological importance, 

 however, as they are not of general occurrence in the Acrididae. 



Continuous with the upper (morphologically posterior) 

 edges of the rami are the ventral lobes (vl), two slender, sub- 

 erect, valve-like processes, beset with minute spinules. They are 

 straight, close together, and bound the genital aperture behind. 

 They are covered in front by the dorsal lobes, (dl), a bilobed flap, 

 which is an extension of the penis roof. 



The inner surface of the ventral lobes is continuous, in this 

 species, with the apices of the parameres (ectoparameres, pm). 

 These pass ventrad a short distance, then bend sharply dorsad 

 and again ventro-cephalad, expanding into a pair of divergent, 

 wing-like plates (the endoparameres, pmb), which lie beneath 

 and between the endapophyses, with which they have powerful 

 muscular connections. 



Lying between the endoparameres, where they most closel}^ 

 approach one another, is a small sac, formed, like the paramere 



