• STUDY ON THE DEATH-FEIGNING OF BELOSTOMA 31 



would extend the legs out stiffly as before, but this rigid state 

 would again be maintained only for a few seconds. This ex- 

 periment was repeated at intervals of five and ten hours with 

 always similar results until the insect became too weak to re- 

 spond. Decapitated Nepas w^ere kept alive for seven days in 

 a dish with just enough water in it to keep the bottom moist. 



Hundreds of Belostomas were decapitated to determine the 

 effect on the death feint. With the removal of the supra- 

 oesophageal ganglia, there is a marked variability in the be- 

 havior of the specimens. It was absolutely impossible to force 

 some of the headless individuals to assume the usual death- 

 feigning attitude. Robertson (23, p. 417) also found that in the 

 sluggish species of spider " (Celaenia excavata), the 'sham-death' 

 posture cannot be induced without the head ganglia * * * ." 

 Most of the bugs, however, from which the head has been severed, 

 could be induced to assume the usual death-feigning attitude 

 through the method usually employed to bring about the inert 

 state, but that marked firmness and stiffness of the limbs, so 

 characteristic of the intact insects, was very weak and of only 

 short duration and often even entirely absent. Often this 

 muscular rigidity could only be brought about by gently stroking 

 the abdomen with a camel's hair brush, but as soon as this was 

 discontinued, the legs would sprawl apart and become flaccid. 

 With every stroke of the camel's hair brush over the body of a 

 specimen w^hose legs were held in the characteristic death-feigning 

 attitude, there would be a marked muscular contraction of the 

 legs, but the instant the stroking ended, the legs would spread 

 apart and show evidence of limpness. If the tibiae of the 

 posterior pair of legs of a specimen in the same attitude were 

 raised with a tooth-pick, the tarsi would bend down as if the 

 stimulation threw the muscles in a state of contraction. It 

 appears, seemingly, that the contact stimulus sets up a reflex 

 which brings about a weak contraction of the leg muscles, rather 

 than that the tetantic condition was brought about through a 

 death feint. It may be possible, however, that these reactions 

 are connected with a death feint of very short duration, due as 

 Holmes (12, p. 211) believes, "to the heightened irritability 

 which normally follows when the inhibiting influence of the 

 supra-oesophageal ganglia is not exerted." Again, the very 

 much weaker response may possibly find its explanation in the 



