STUDY ON THE DEATH-FEIGNING OF BELOSTOMA 



19 



and caused to feign death at the temperature of the atmosphere 

 at 31° to 32° C. The average of the first six successive death 

 feints of each individual were : 6.3, 7.1, 7.6, 9.1, and 11. 5 min- 

 utes, the total average being 8.3 minutes. 



With Nepa, two separate experiments were performed, in each 

 of which two lots of specimens of eight or ten were made to 

 feign, one at a high temperature and the other at a temperature 

 considerably lower. In both of these experiments, all of th- 

 water-bugs were first kept for three or four hours in the teme 

 perature at which they were afterwards put into the inert state. 

 The averages of the first death feints under these conditions were : 



TABLE IV. 



Experiment 1. 



Nepas kept at 34° to 35° C, 4 minutes. 

 " 28° " 29° "11.8 



Experiment 2. 



Nepas kept at 25° C, 13.7 minutes. 



" 16° to 17°C., 27.6 



13. The effect of a low temperature on the duration of the death 

 feint: A considerable amount of difficulty was experienced in 

 determining the effect of a low temperature upon the duration 

 of the death feint in Belostoma. A number of experiments were 

 performed in which the transition in temperature from the water 

 to the atmosphere was not very great, thus avoiding a sudden 

 shock effect; these experiments were also carried on at a time 

 of the year, in which the aquatic bugs had been surrounded 

 with a low temperature in their natural environment, the spe- 

 cimens in the first three experiments, table V, being taken 

 after a thin coating of ice had formed over the water. In all 

 of the experiments, six or more Belostomas were caused to feign 

 at least five successive times. The following table shows the 

 transition in temperature from the water to the atmosphere, 

 and the total average of the death feints of all the specimens in 

 each experiment; 



TABLE V. 



