256 WASP STUDIES AFIELD 



erect; at a nearer approach they fly downward about the 

 head of the intruder and often are free with stings. After 

 a few seconds of aggressive buzzing, most of them escape 

 to return later; those which remain are usually the queen 

 and the youngest workers. It seems that the young work- 

 ers are slow to learn to defend themselves by offensive 

 actions. True, they can sting if handled, but they do not 

 fly away from the nest when it is in danger, nor do they 

 attack an observer, but remain on the nest. When teased 

 with a straw, they walk a short distance and stop; when 

 followed, they escape by the first crack in the wall. In our 

 observations, these newly-hatched ones, when ousted in this 

 manner, seldom were able to return to the nest, this fail- 

 ure to return evidently being due to their lack of knowledge 

 of their environment. 



Now this was precisely the condition in nest 19 in 

 Experiment VI ; the old workers flew at our approach and 

 the queen and three young workers remained and were 

 taken for the experiment. The queen returned and these 

 new workers were all lost. (See Experiment VII for addi- 

 tional observations on workers of nest 19.) 



Experiment VII 



July 7. This is merely a repetition of the foregoing ex- 

 periment. A second lot of wasps were liberated at the 

 same place and date as before, but two hours later, at 

 10: 30 a. m. 



Nest 19. After the first lot had been taken and released, 

 the older workers which escaped us returned to the nest. 

 Three of these were taken and marked differently, to dis- 

 tinguish them with certainty from those from this nest used 

 in previous experiments, and released as per account. 



When the nests were examined at II : 01 o'clock, two of 

 these workers had already returned, which satisfies us in this 



