STUDY ON THE DEATH-FEIGNING OF BELOSTOMA 17 



aquatic bug is still under the influence of the death feint. A 

 little later Belostoma scurries to the bottom of the aquarium. 



In order to have as slight a shock effect as possible, a dozen 

 Belostomas, which had been kept in water at 19° C, were picked 

 out of the water, caused to feign death and then carefully trans- 

 ferred to the surface film of the same water. The temperature 

 of the room was kept at 21° to 22° C. The following figures show 

 the duration of the first death feint in the twelve specimens, the 

 dashes indicating that the bug came out of the feint almost 

 immediately after coming in contact with the water or feigned 

 less than half a minute: — , — , — , .5, .5, .5, i, i, 1.5, 3.5, 9.5 

 and 23 minutes. 



The previous experiment was repeated with seven Belostomas 

 under similar conditions, but each specimen was caused to 

 feign five successive times. The averages were: ^.;^, 4.6, 

 II. 5, 12.7, 14.5, 16.7 and 18 minutes; the total average was 

 II. 6 minutes. 



In the experiment under table II, the difference in temper- 

 ature of the water and the atmosphere was identical with these 

 conditions in the present experiment. The total average of the 

 first five successive death feints of the former, however, was 

 24.9 minutes, while in the latter it was 11.6 minutes. It is evi- 

 dent, thus, that the effect of placing Belostoma on the surface 

 film of the water diminishes the duration of the death feint. 



It occurred to us now that Belostoma would probably feign 

 below^ the surface of the water. A toothpick was fastened horizont- 

 ally by one end about an inch below the surface of the water^ while 

 at the other or free end the feigning insect was placed so that 

 this end of the toothpick passed between the middle and hind 

 pairs of legs. The experiment, however, had its faults, for as 

 soon as the extreme muscular contraction of the limbs relaxed 

 somewhat, the legs gradually spread apart and the bug rose to 

 the surface film. This experiment was repeated with the 

 same individual again and again. As in the preceding experi- 

 ments, there was a considerable variability in the duration of 

 the feint in those specimens which could be induced to feign under 

 these conditions. Although there were some bugs which would 

 feign below the surface of the water for a short time, we finally 

 succeeded in getting one to feign 6.5 minutes, another 11, a third 

 12, and a fourth 13.5 minutes, the last continuing to feign four 



