502 ANNUAL KEPORT SMITHSONIAN INSTITUTTON, 1917. 



it extends the anterior forelegs straight forward and the hind legs 

 backward, all clinging close to the body, except the tibise of the last, 

 which are set at a slight angle. This position represents a state of 

 most perfect catalepsy and at tl^e same time of perfect mimicry, be- 

 cause the insects retain it longest and in it most resemble inanimate 

 objects, like sticks. 



The insect thus lying still can be raised onto its legs without dis- 

 turbing the cataleptic state. To do this one need but carefully bend 

 its legs by means of forceps and they will retain the position given 

 them; then it must be turned over and placed on its legs. During 

 this operation some reflex stirring is observed occasionally, but it 

 afterwards remains rigid in the given pose. 



Standing on its legs the insect may be given any desired pose, not 

 excepting most unnatural and difficult ones. It ma}' thus be made to 

 stand on three legs, by raising one of the middle ones. It may be 

 made to stand on the four front legs and hold the hind ones raised. 

 He sometimes succeeded in making it stand on three legs on one side, 

 the end of the abdomen serving as support for the other side. The 

 antennse, too, may be extended forward, put back or placed at right 

 angles to the body — and they Avill retain the position given them. 

 Finally, the abdomen may, for instance, have its end bent upward 

 almost to the vertical, a position never assumed by the adult insect. 



Under a highly cataleptic state the insects can be stood on their 

 heads, supported by the first two pairs of legs, or even the first alone, 

 and the antenna pointing the other way. One insect remained in 

 this position for 41 hours. 



These simple experiments show that the phasmid's state of rest 

 is diiferent from the usual state of rest of animals. It differs radi- 

 cally from its state of activity which should be the normal but which 

 in fact is more rare and of shorter duration. The resting insect 

 passes into the active state after strong provocation as, for in- 

 stance, when the end of its abdomen is pinched with the forceps 

 or struck with it, etc. Sometimes the insect wakes also when an 

 antenna or leg is pinched or it is simply breathed on, when it jumps 

 up, takes several swings and runs. But sometimes it stirs, makes 

 reflex motions, and returns to quiescence. 



Wlien awake Carausius reacts to all strong stimuli with energetic 

 running. Thrown on its back, it immediately turns over and jumps 

 to its long legs. Caught by the tail it strains with all six legs to ex- 

 tricate itself and run forward ; caught by the antennee it pulls back- 

 ward. Any of its appendages raised are forthwith lowered and run- 

 ning away is induced. Thus no trace is left of the plasticity of the 

 appendages observed in the resting insect. It reacts like a normal 

 living animal. 



