2o6 'Journal of Comparative Neurology and Psychology. 



individuals is very variable, as may be seen by a glance at the 

 accompanying tables. In all the experiments the insects were 

 subjected as nearly as possible to the same amount of handling, 

 and exposed to light of the same intensity. The Ranatras were 

 picked out of the water, and, after the legs were bent back 

 against the body, the specimens were stroked a certain number 

 of times and laid on the bottom of a glass dish. Each dish w^as 

 covered by a glass plate and kept partly immersed in water of the 

 desired temperature which was indicated by a thermometer 

 placed in the dish. All of the conditions except temperature to 

 which the different lots of specimens were exposed were made 

 practically the same. 



In one experiment nine Ranatras were exposed to a tempera- 

 ture of 35° C., and an equal number kept at the temperature of 

 the room which was 21° C. In the first lot the duration of feints 

 in minutes in different specimens was as follows: 8, 8, 9, 10, 14, 

 18, 21, 25, and 40 — giving an average duration of feint of seven- 

 teen minutes. In the lot kept at a temperature of 21° C. all of 

 the specimens, without exception, were still feigning after an 

 hour and five minutes w^hen the experiment was discontinued. 



In a second experiment eight specimens were kept at a tem- 

 perature of 30° C. and eight others at a temperature which varied 

 from 10° C. to 14° C. while they were kept under observation. 

 The duration of the feints in the two cases was as follows: 



Specimens Kept at io -C.14 C 



Specimens Kept at 30 C. 



65 



145 

 146 



147 

 147 

 149 

 160 



13 



17 



102 



107 



Average 137 minutes. 



Average 43 minutes. 



In a third experiment one lot of seven specimens was kept at 

 the temperature of the room which was 22° C. while eight other 



