The Hunting Wasps 



conducted as follows : two sound and healthy 

 Ephippigers, just as I picked them up in the 

 fields, were imprisoned without food, one in 

 the dark, the other in the light. The second 

 died in four days, the first in five. This dif- 

 ference of a day is easily explained. In the 

 light, the insect made greater exertions to re- 

 cover its liberty; and, as every movement of 

 the animal machine is accompanied by a cor- 

 responding expenditure of energy, a greater 

 sum total of activity has involved a more 

 rapid consumption of the reserve force of the 

 organism. In the light, there is more rest- 

 lessness and a shorter life; in the dark, less 

 restlessness and a longer life, while no food 

 at all was taken in either case. 



One of my three stabbed Ephippigers was 

 kept in the dark, fasting. In her case, there 

 were not only the conditions of complete ab- 

 stinence and darkness, but also the serious 

 wounds inflicted by the Sphex; and neverthe- 

 less for seventeen days I saw her continually 

 waving her antennae. As long as this sort 

 of pendulum keeps on swinging, the clock of 

 life does not stop. On the eighteenth day, 

 the creature ceased its antennary movements 

 and died. The badly-wounded insect there- 

 fore lived, under the same conditions, four 

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