294 Annals Entomological Society of America [Vol. XII, 



in a corresponding groove in the ventral valvulas (Fig. 41), 

 but as the parts are soft no union is thus obtained. The dorsal 

 valvulae do not lie so flat as in Timema, but the primitive widely 

 separated position is retained, their bases not becoming arched 

 dorsad over the inner valvulse. Their only strongly chitinized 

 parts are the superior apophyses which are well developed and 

 a small process just above the angle with the ventral valvula;, 

 and apparently representing the inferior apophyses. There is 

 no trace whatever of the valvifer, but there is a small process- 

 (pap) which seems to belong to the lower extremity of the ninth 

 tergal apodeme. Both valvifer and apodeme, however, may be 

 well developed in the Phasmoidea as shown by Lacaze-Duthiers 

 in the genus Acrophylla. Their absence in Diapheromera is a 

 degenerative feature. The basivalvulas are also absent in this 

 genus. The subgenital plate is of large size, but much smaller 

 than in many other genera. The tenth segment is large, with 

 an extensive sternal area, but the supra-anal plate and para- 

 procts, though prominent are much sm_aller than in Timema. 

 The cerci are also relatively smaller. 



There is considerable variation in the Phasmids in the size 

 of the subgenital plate, the relative lengths, form and position 

 of the valvulae, but a firm, coherent structure, such as the 

 ovipositor of the Orthoptera and Grylloblattoidea, does not, 

 so far as we are aware, occur in this order. The apparently 

 primitive form of the Phasmoid ovipositor may be largely due, 

 as already suggested in the case of Timema, to imperfect or 

 arrested development, but at the same time, it is probable that 

 the Phasmoid ovipositor never reached a high degree of develop- 

 ment. 



Mantoidea (Mantidas). 



Of the single family comprising this order two species were 

 studied, Stagmomantis Carolina L. and Mantis religiosa L. 

 They are so much alike in the parts with which we are con- 

 cerned, that we may confine our attention in the main to the 

 former, this having been the form which was most thoroughly 

 studied. 



In Stagmomantis (Figs. 44-49) there is a marked abbreviation 

 of the eighth and ninth tergites, which also extend a shorter 

 distance ventrad on the sides than the seventh and preceding 



