DISTRIBUTION OF MEMORY 225 



wasps employ of finding their way to the nest, which 

 absolutely excludes the assumption that they are 

 guided reflexly by known or unknown stimuli, and 

 which indicates that they find their way through 

 memory. An Ammophila had a hole in a flower-bed 

 in my front yard. The wasp, of course, left the yard 

 Hying. To\ ,irds noon I saw an Ammophila running 

 on the sidew ilk of the street in front of the yard 

 carrying a caterpillar in its mouth. The weight of 

 the caterpillar prevented it from flying. The yard 

 is separated from the street by a cemented stone 

 wall. I noticed that the wasp repeatedly made an 

 attempt to climb upon the wall, but kept falling 

 down. Suspecting that it might have its nest in 

 the yard I was curious to see whether and how it 

 would find the nest. 



It followed the wall until it reached the neighbour- 

 ing yard, which had no wall. It now left the street 

 and crept into this yard. Then crawling through 

 the fence which separated the two yards, it dropped 

 the caterpillar near the foot of a tree, and flew 

 away. After a short zigzag flight it alighted on 

 a flower-bed in which I noticed two holes. It soon 

 left the bed and flew back to the tree, not in a 

 straight line but in three stages, stopping twice on its 

 way. At the third stop it landed at the place where 

 the caterpillar lay. The caterpillar was then dragged 

 to the hole, pulled into it, and covered with sand. 



As the wasp only walks to the hole when carrying 

 a caterpillar, it is impossible to say that it followed a 



