CH. V] WASPS 153 



On the other hand there is evidence that in other cases 

 the sense of sight is of prime importance. In 1893, a 

 great " wasp year," I found a nest of V. sylvestris in an 

 old meat-tin. In order to watch it more conveniently I 

 moved it a few feet: the wasps witnin the nest, when 

 they came to the exit, paused before taking flight, then 

 they flew to and fro repeatedly over the nest, gradually 

 enlarging the range of flight until they reached the spot 

 where the nest had previously been lying: here all was 

 familiar and they then went straight away. Of those 

 who were abroad from the nest at the time of removal 

 every one returned to the old position and hovered 

 restlessly over it; very few, if any, of these discovered 

 the nest in its new position. After an interval, wasps 

 began returning direct to the nest where I had placed 

 .it, without going to the old site at all: these were almost 

 certainly individuals who had been within the nest at the 

 time of removal and had taken its bearings afresh before 

 starting forth on their journeys. 



I have observed precisely similar behaviour in bumble- 

 bees kept in captivity. A very slight displacement of the 

 box containing the nest was invariably followed by a 

 careful survey of the surroundings. The bumble-bees on 

 leaving the recently moved box always hovered to and fro 

 over it, facing it, before flying out of the open window. 



Again the fossor, Ammophila hirsuta, after carefully 

 concealing her burrow with a stone, loose sand and dead 

 grass roots, takes accurate note of its position and con- 

 stantly assures herself of her ability to return to it from 

 objects in the immediate vicinity. 



