STUDY ON THE DEATH-FEIGNING OF BELOSTOMA 7 



once righted, the insect, if it does not feign again, slowly draws 

 its legs into a walking position. After remaining quiet in this 

 attitude for a short time, another peculiar phenomenon may 

 take place. One set of legs are slowly extended, the insect 

 pulls itself suddenly forward and stops for a short time; now 

 the other set of legs are extended, the insect pulls itself suddenly 

 forward and stops. In this way Nepa may move forward in 

 jerks several times, but finally these movements cease and the 

 insect runs rapidly away. It is only when it runs rapidly away 

 that Nepa is entirely out of the death feint. 



Preyer ' observed in the guinea pig that loud noises, sudden 

 visual impressions, a breath of air, or a contact stimulus causes 

 the animal to right itself. Belostoma also can be brought out 

 of the death feint by blowing a breath of air against it. Seizing 

 one of the legs with a pair of forceps frequently produces the 

 same result. A common house-fly or another Belostoma crawling 

 upon the feigning specimens may sometimes cause an instan- 

 taneous righting reaction. 



A specimen is often aroused from its immovable state without 

 any apparent external stimulation. It may feign only a short 

 time and before giving any evidence of a gradual relaxation of 

 the leg muscles, it may spread its legs, brace the tip of the ab- 

 domen against the substratum and with the aid of its swimming 

 legs make vigorous efforts to right itself. Whether the contracted 

 leg muscles of Belostoma relax suddenly and a new strong 

 contraction sets in, bringing about the righting reaction, or 

 whether a new energetic contraction is superimposed upon the 

 first, we had no way of determining. Verworn (27, p. 25), 

 however, has determined from rather difficult experiments 

 which he performed on the guinea pig, "dass der Muskel, w^elcher 

 sich wahrend der bewegungslosen Riickenlage des Thieres in 

 tonischer Contraction befindet, bei jedem Aufstehversuch plotz- 

 lich einen starken Contractionszuwachs erfahrt und nicht eine 

 Hemmung, wie etwa bei den bekannten Versuchen von Heiden- 

 hain und Bubnoff. " 



6. Apparent insensibility to pain while in the death feint: One 

 of the most remarkable peculiarities of the death feint in some 

 Arthropods is the fact that they can be severely mutilated or 

 dismembered, or even roasted alive without showing any appar- 



1 Trans, from Verworn's (27, p. 6) paper. 



