STUDY ON THE DEATH-FEIGNING OF BELOSTOMA 27 



are tilted upward. Most of the bugs, however, do not give these 

 reactions before coming out of the feint. 



A large number of insects experimented upon with the electric 

 light in this manner, gave no reactions previous to coming out 

 of the death feint, but simply righted themselves and usually 

 endeavored to escape by fleeing away from the light. One 

 noticeable peculiarity of some of the fleeing individuals was the 

 swaying movements of the body, combined with the hurried 

 movements of escape. When these fleeing specimens were allowed 

 to run at large on the floor, many ran in a large circle, the 

 body being tilted toward the light. It w^as found that sooner 

 or later most of these specimens would finally return to the light. 

 Some bugs, however, would simply right themselves after com- 

 ing out of the feint and remain motionless for a time, but later 

 they would follow the Hght, while still others would right them- 

 selves and follow the light immediately. 



VII. THE EFFECT OF MUTILATION ON THE DEATH FEINT. 



1 8. The effect of decapitation on the death feint: Preyer and 

 Verworn have both worked on the effect of decapitation on 

 the so-called hypnotism of vertebra ted animals. Preyer ' 

 decapitated a hen and two cocks and believes that his results, 

 " stehen im Einklang mit der Annahme, das auch gekopfte 

 Thiere durch starke tactile Reize kataplegisch werden konnen." 

 Verworn (27, pp. 57-8) repeated the experiments of Preyer and 

 concludes, " Immerhin mochte ich die Moglichkeit nicht bestreiten. 

 Aber wie dem auch sei, auf keinen Fall wiirde aus diesem Umstand 

 der Schluss gezogen werden diirfen, dass beim intacten Thiere die 

 Ursachen fvir den Eintritt der Bewegungslosigkeit in abnormen 

 Korperlagen ihre Localisation im Riickenmark hatten, - - - - ." 



Robertson (23, p. 417) concludes that among the invertebrated 

 animals " the ' sham-death ' reflex is carried out without the aid 

 of the abdominal nerves, and in the active species [Epeira (pro- 

 ducta?) and Amaurobius sp.?] can be performed in an altered 

 manner by the thoracic ganglia alone, or even by the ganglia 

 of the posterior or two anterior segments of the thorax alone. 



With the supra- and sub-oesophageal gangHa removed 



the reaction is still carried out in the active species, but it is 

 now- weaker, has a longer latent period (in Epeira sp. at least, 



^ Quoted from Verworn's (27, p. 56) paper. 



