4 Trans. Acad. Sci. of St. Louis. 



the other members of the group have ? In other Orthop- 

 tera such as the mole-cricket, we find the forelegs modi- 

 fied for digging ; in the grasshopper, cricket and katydid, 

 the hind legs are developed for jumping, and in the 

 roaches all of the legs are specialized for running. In 

 all of these insects the thorax which carries all three 

 pairs of legs is comparatively small, just as is the meso- 

 and metathorax in the mantis, but here the prothorax 

 which carries these forelegs is greatly enlarged. PI. 

 XVIII, Fig. 1 shows clearly the comparative size of the 

 parts. 



To the meso- and metathorax are attached the two 

 pairs of wings and the two hind pairs of legs. When 

 nymphs are caught by the hind legs, they frequently 

 walk away, leaving the limbs in one's hand. These un- 

 doubtedly regenerate, since individuals are not infre- 

 quently found with one appendage which is smaller than 

 the others. In the younger nymphs, which are fast mov- 

 ing creatures, all six legs are used for locomotion. The 

 adults are slow moving insects, especially so the females ; 

 they seldom use the forelegs for walking, but depend 

 upon the hind legs alone for that purpose and keep the 

 forelegs free for grasping prey. 



The size and color of the wings differ in the sexes, as 

 the illustrations show. The male can fly for a consider- 

 able distance, much in the manner of a locust's flight, 

 but the adult female cannot fly, partly on account of her 

 aborted wings and partly because of being heavily laden 

 with eggs, although she spreads her wings to ease the 

 fall when she drops to a lower surface. The males occa- 

 sionally come to the lights, but I have yet to observe the 

 first female there. 



The function of the cerci is as yet little understood. 

 Sharp (1895, p. 247) thinks that they assist the insect in 

 emerging from the egg-case, and I shall later show how 

 in the adult they may serve as sense-organs in the fash- 

 ioning of the egg-case. 



