54 Annals Entomological Society of America [Vol. XV, 



ninth sternum undivided and without styli, usually but little 

 modified as a hypandrium; cerci typically elongate and multi- 

 articulate; supra-anal plate extremely variable, sometimes 

 simple and indistinctly separated from the tenth tergite, 

 sometimes modified to form complex copulatory organs, which 

 may be freely projecting and bent forwards to occupy a groove 

 on the dorsum of the terminal segments, or concealed in a 

 pocket which divides mesially the 10th tergum; paraprocts 

 usually large and often fused with bases of cerci, frequentty 

 bearing copulatory hooks; penis, when present single (rarely 

 bifid?), eversible, with or without a virga; sometimes with 

 parameres. 



Orthoptera. Terminal segments more or less shortened; 

 ninth sternum enlarged to form a hypandrium, sometimes 

 divided by a transverse suture, with or without styli; cerci 

 moderate or short, unsegmented (with rare exceptions, v. 

 Tridactylus), often modified as claspers; with a small basipodite; 

 supra-anal plate generally well developed, sometimes divided 

 into a. separate 11th tergite and telson (Acrididae), not concealed 

 by the tenth tergum ; paraprocts variable, rarely (Tridactylidas) 

 bearing cercus-like processes; penis generally large, the ejacu- 

 latory duct emptying through a spermatophore sac, into w^hich 

 (typically) the bases of the parameres are retracted ; a pseudo- 

 sternite typically present, forming a collar over dorsum of penis 

 and prolonged ventrad into a pair of rami, from which arise 

 inward projections or apophyses for muscular attachment. 

 Numerous modifications of this plan occur. 



Phasmoidea. Terminal segments elongated, the genitalia 

 being ventral instead of posterior in position; ninth sternum 

 transversely divided, a small sternite being separated from a 

 large, more or less-flap-like hypandrium (united coxites), 

 without styli; cerci short, generally modified as claspers; supra- 

 anal plate usually vestigial or absent, paraprocts moderate or 

 prominent; penis apparently situated on the ninth sternal 

 region, in reality on the elongated and secondarily chitinized 

 interval between the ninth and tenth sterna, stout, asym- 

 metrical, more or less distinctly divided into right and left 

 lobes, the right overlapping the left, the ventrally placed 

 genital aperture thus directed somewhat dextrad; dorsal surface 

 somewhat chitinized and bearing in some forms a pair of 

 cornua (parameres?). 



