lOlO'] Walker: Structure of Orthopteroid Insects 311 



ninth tergal apodeme variable in development; ovipositor 

 generally of considerable size, but the three pairs of valvulse not 

 firmly chitinized; dorsal valvulae widely separated at base, 

 not covering the inner pair and without a superior intervalvula; 

 superior and inferior apophyses present, the latter widely 

 separated; inner valvulae united dorsal except distally and 

 having sometimes an ineffective tongue-and-groove connection 

 with ventral valvulse; no intervalvular membrane or inferior 

 intervalvula; tenth segment with distinct sternal region; cerci 

 short, unsegmented; supra-anal plate usually small, paraprocts 

 prominent. 



Mantoidea — Tergites of segments eight and nine shortened; 

 seventh sternum forming a very large subgenital plate concealing 

 remaining sterna and ovipositor; eighth sternum greatly 

 reduced; ninth, vertical or subvertical; valvifers separated from 

 tergites, but connected across intervening membranous area 

 by the intersegmented apodeme with eighth and ninth tergites; 

 ovipositor of considerable size with three pairs of valvulae, 

 basivalvulie heavily chitinized, widely separated, but con- 

 nected by a chitinous arch or transverse bar ; valvulae of irregular 

 form, and imperfectly chitinized; dorsal valvulae covering inner 

 pair, united at. extreme base; superior intervalvula connecting 

 both dorsal and inner valvulae; dorsal valvulae with two pairs 

 of apophyses, the inferior apophyses joined by a large inferior 

 intervalvula; inner valvulae free from the latter without 

 intervalvular membrane, but the internal (basal) prolongations 

 of the rami connected by a thin plate which bears the median 

 apodeme of the superior intervalvula; ventral valvulae engaging 

 inner by a feeble tongue-and-groove j oint . Cerci subcylindrical , 

 many-segmented; supra-anal plate vestigial, concealed by tenth 

 tergite; paraprocts little chitinized. 



Nymph {Mantis) similar to that of Blattoidea, but styli 

 in last stage very minute. 



Blattoidea — Abdominal segments flattened; tergites of eight 

 and nine shortened; seventh sternum forming a very large 

 subgenital plate, concealing remaining sterna and ovipositor; 

 eighth sternum greatly reduced; ninth obliquely inclined; 

 valvifers very large, separated from tergal margins, but con- 

 nected across intervening membranous area with the eighth 

 and ninth tergites by the intersegmented apodeme; ovipositor 

 small,, the three pairs of valvulae of irregular form, more or less 



