STUDY ON THE DEATH-FEIGNING OF BELOSTOMA 15 



present experiment. The total average of the first five succes- 

 sive death feints of the former, however, was 24.9 minutes, while 

 in the latter it is but 6.8 minutes. It is evident, therefore, that 

 the drying of the body of Belostoma causes a marked diminution 

 of the death feint. 



In another experiment, eight Belostomas were placed into a 

 glass jar lined with blotting paper, and were there exposed to 

 the atmosphere at 21° to 22° C. Twelve hours later all the 

 specimens were caused to feign three successive times, and it was 

 found that every single death feint was less than five minutes. 

 Sixteen hours after being confined in the glass jar, three indi- 

 viduals had died and one could not be induced to assume the 

 usual death-feigning posture. The four remaining insects were 

 put into three successive death feintS' of which the total average 

 was one and one-half minutes. Twenty hours after being ex- 

 posed to their dry surroundings, three of the remaining bugs 

 had died; the other two were too weak to assume the usual 

 death-feigning posture and these died two hours later. 



If the behavior of the eight specimens in the previous exper- 

 iment is compared with that of the ten Belostomas used in the 

 experiments in determining, how long successive death feints 

 can be continued, it will be noticed that both lots show a weaker 

 reaction towards the end of the experiments. In all prob- 

 ability, this weaker response in the latter cannot be wholly 

 attributed to fatigue, but must, in part at least, be due to the 

 effects of dryness upon the organisms. It is evident further that 

 dryness causes a marked diminution in the duration of the death 

 feint. The decrease wdth successive trials in the duration of the 

 feint and also the cessation of the death feint must be attributed 

 in part to the effects of dryness rather than entirely to fatigue. In 

 all probability it was also the effect of dryness which caused the 

 death of the ten Belastomas after they had feigned eight hours 

 on an average in the above experiments. 



10. The effect of moisture on the death feint: The object of 

 the following experiment was to determine what effect moisture 

 has upon the duration of the death feint. Twenty Belostomas 

 were taken out of water at 18° C. and caused to feign death at 

 the normal temperature of the room with their backs resting 

 upon some wet blotting paper that had been soaked in the same 

 water from which the individuals had just been taken. Imme- 



