HABIT-FORMATION IN A WASP (VESPA SP.). 285 



always induced prolonged hovering before and alighting on the 

 plug, with consequently large increases in the recorded times. 

 In the ninth trial the "Wasp returned from the feeding-grounds 

 directly to the rabbit-burrow, in front of which she planed to and 

 fro for a few moments. Though in the first trial the Wasp 

 reacted positively to the nest when she was in exactly the same 

 position, on the present occasion she failed to do so, and proceeded 

 to the plug, where she hovered for a little and then flew quickly 

 into the rabbit-burrow. The experience illustrates well the 

 chain-reflex nature of the new habit which had been formed. 

 The movements to be performed in traversing the rabbit-burrow 

 to the nest could not now be released at the entrance to the burrow. 

 The stimulus of the plug was a necessary link in the chain. 



The trials given on the fourth day did not differ in general 

 features from those given on the third. At the first and the 

 eleventh trials the Wasp, after hovering before the plug, flew to 

 the entrance of the rabbit-burrow, where she suddenly turned 

 and flew back to the plug. There she hovered again before 

 proceeding finally into the burrow. The twelfth trial was even 

 more remarkable, in that the Wasp returned twice to the plug 

 after reaching the entrance to the burrow. From the notes of 

 these trials it is hard to tell whether the plug failed to give an 

 adequate release of the movement into the burrow, or some new 

 sensation derived from the unsatisfactory material of the plug 

 produced a delayed inhibition of the movement and a compulsory 

 return to the plug. 



The trials of the eighth day showed perfect retention after an 

 interval of about ninety hours. Following these retention trials, 

 two returns were observed without the plug having been placed 

 in the tunnel. In the first instance the persistence of habit and 

 an absence of immediate reaction to the actual environment were 

 demonstrated. The Wasp hovered before the tunnel as if the 

 plug were still there. But at the second trial she came in at 

 top speed and dived abruptly into the tunnel. 



On leaving the nest the Wasp made locality-studies before 

 the mouth of the tunnel after the first sixteen trials. Thereafter, 

 no locality-studies occurred unless the plug had to be changed 

 or remodelled. Whenever this was the case, the W T asp made a 

 study of the locality. In the last two experiences of the eighth 



