1922] Walker: Structure of OrtJiopteroid Insects 55 



Grylloblattoidea. Terminal segments not elongated, 

 the tenth small but prominent; its lateral lobes prolonged 

 ventro-mesad into a pair of asymmetrical copulatory arms; 

 ninth sternum very large and asymmetrically divided into 

 sternite and coxites bearing styli, the coxites probably serving 

 as claspers; cerci segmented as in the female, with small basi- 

 podite; penis large, divided into two asymmetrical lobes, the 

 right overlapping the left, the genital aperture probably in 

 the intervening fissure; dextral lobe bearing an irregular, 

 chitinous process; sinistral lobe with no chitinous process, but 

 with an eversible membranous sac; a pair of plates bearing 

 dextral copulatory processes near the dextral coxite, which 

 bears an additional process; the processes together forming a 

 clasping apparatus on the right side. 



Blattoidea. Terminal segments slightly abbreviated, but 

 the tenth tergum prolonged into a flap which serves as a supra- 

 anal plate; ninth sternum forming a large, undivided, but 

 styligerous hypandrium; cerci of moderate length, flattened, 

 multi-articulate ; supra-anal plate disappearing in early nymphal 

 life; paraprocts flattened, generally more or less chitinized 

 beneath and often bearing asymmetrical copulatory hooks, or 

 a single dextral hook; penis asymmetrical, consisting of a median 

 lobe or process, directed more or less dextrad, bearing the 

 genital opening, which is sometimes situated on a retractile 

 virga, and two dissimilar lateral lobes, of which the dextral 

 tends to overlap the sinistral, these lobes bearing the para- 

 meres (?) and frequently other accessory chitinous processes. 

 One of the parameres may be modified into a retractile copu- 

 latory hook; the dextral lobe may bear a clasper. 



Mantoidea. Terminal segments but little abbreviated, 

 the tenth tergum forming a flap which serves as a supra-anal 

 plate; ninth sternum forming a very large, but undivided 

 hypandrium, bearing styli; cerci of moderate length, less 

 flattened than in the Blattoidea, multi-articulate; supra-anal 

 plate vestigial and membranous; paraprocts broad, somewhat 

 flattened, unchitinized in the types studied; penis strongly 

 asymmetrical, consisting of two dissimilar paramere lobes, the 

 sinistral very large, the dextral small and overlapping the 

 sinistral; ejaculatory duct wide, opening on the mesial surface 

 of the sinistral lobe, with which the vestigial penis-lobe is 



