The Instinct of Feigning Death 213 



also. In a sluggish spider Celaenia Robertson found 

 that "The sham death posture cannot be induced 

 without the head ganglia." Schmidt finds that in 

 Carausius the death feint entirely disappears after 

 the removal of the brain. My own experiments on 

 Ranatra showed that removal of the brain caused 

 a marked diminution in the duration of the feint, 

 although the response could still be induced in de- 

 cerebrate specimens. If a feigning individual be cut 

 in two across the prothorax the posterior part often 

 continues to retain its rigidity for some time and 

 may be thrown back into the death feint again if it 

 is picked up and stroked. Similar results were ob- 

 tained in Belostoma and Nepa by the Severins, who 

 have investigated the role of the nervous system in 

 especial detail. The cataplectic state which Preyer 

 and Verworn found could be induced in decerebrate 

 fowl may be allied to the conditions described above. 

 One marked characteristic of the death feint is 

 an apparent insensibility to pain. De Geer in writing 

 of a boring beetle Anoblum pertlnax says that "you 

 may maim them, pull them limb from limb, roast 

 them over a slow fire, but you will not gain your 

 end; not a joint will they move, nor show by the 

 least symptom that they suffer pain. A similar 

 apathy is shown by some species of saw-flies (Ser- 

 rifera), which when alarmed conceal their antennae 

 under their body, place their legs close to it, and 

 remain without motion even when transfixed by a 

 pin. Spiders also simulate death by folding up their 



