1922] Walker: Structure of Orthopteroid Insects 47 



similar and also resembles that of P. Juliginosa. The part 

 which represents the dorsal process is bent up sharply distad 

 and terminates in a large chitinous knob. The dorso-mesial 

 surface is marked by two longitudinal furrows and bears another 

 large. chitinous tubercle. 



Although it is impossible to determine with certainty from 

 the few types studied which of the various processes borne by 

 the sinistral lobe in Periplaneta is the homologue of the eversible 

 hook of Blattella and Parcoblatta, it appears probable that it is 

 the long ventro-lateral process, this being the longest, most 

 independent, and apparently the most constantly present of 

 these parts. It is also lodged within a furrow formed by the ^^ 

 other two parts, which may therefore be possibly looked upon 

 as secondary outgrowths from the paramere sheath. 



By reason of the resemblance of the sinistral lobe of Peri- 

 planeta to that of the Mantids, and the non-retractile character 

 of all its processes, it is probably a more primitive type than 

 that of Blattella and Parcoblatta, in spite of its complexity of 

 structure. The symmetrical paraprocts and hypandrium, and 

 possibly the more elongate joints of the cerci may also be marks 

 of primitive organization. 



Mantoidea. 



The male Mantids are very similar to the Blattids with 

 respect to their genitalia and other abdominal structures. 



Only three species were studied: Stagmomantis Carolina L., 

 S. floridensis Davis and Mantis religiosa L. ; and these are all 

 essentially similar in the parts with which we are concerned, 

 so that, unless stated otherwise, the following remarks will 

 apply in particular to one species, 5. Carolina. 



The terga, cerci and anal valves are similar to those of the 

 female, the tenth tergum, as in the Blattids, replacing the supra- 

 anal plate, which, however, remains as a membranous vestige. 

 In some newly hatched Mantids of an unknown species from 

 Japan it is quite distinct and only partly overlapped by the 

 tenth tergite (PI. XI, Fig. 109), a fact which has been pointed 

 out recently by Chopard ('17). 



The ninth sternum is a somewhat elongate plate, sym- 

 metrical and bearing large styli upon its hind margin. This 

 margin is but little excavated in the adults of any of the species 

 seen, but in the young nymphs referred to in the preceding 



