o70 PHIL RAU AND NELLIE RAU 



she approached from the west (a new direction), and she be- 

 trayed extreme confusion, flying back and forth in the region 

 of her tie and finally alighting on a weed near by to rest and 

 readjust her burden and get a better grip upon it with her hind 

 pairs of legs. At this point a train dashed by, passing over her 

 very tie, shaking it violently, and causing her to disappear for 

 seven minutes. Then we spied her up the track, hunting eagerly 

 over another tie which had a wire over it, just like her own. 

 Furthermore, she was searching over only the south end and 

 west side of the ties (this was the location of her nest in her 

 own tie) ; then she seemed to give it up and dashed off down the 

 track to a few feet beyond her nest and resumed the searching, 

 then gradually worked her way back, circling low over the south 

 end of many ties until she came to her own which she recognized 

 at once and wearily entered, carrying all the time her green 

 leaf. After a four-minute rest she dashed off westward again, 

 this time for a fifteen-minute journey. Upon her return she 

 repeated exactly the performance of searching over the ties a 

 little west, then east of her nest, and then working back to the 

 middle position, where lay her nest. At each trip she brought 

 her load of leaf. As she emerged from her crevice after five 

 minutes we caught her and dug out her nest, a neat little pack 

 of leaves about three-fourths inch long. 



It seems to me that she was quick to make use of her newly- 

 acquired knowledge that she could rely upon the rails as guide- 

 lines to her home, and not look to the right or the left of the 

 track. She searched only in the two directions of a straight 

 line, which is far simpler than to search in all directions of the 

 compass, as her ancestors must have done. For is not this 

 deliberate search on either side of her nest analagous to the 

 flight of orientation, commonly seen in the homing of bees and 

 wasps?' Is it not, in fact, itself a flight of orientation so simpli- 

 fied and so deliberately executed that we are able to follow 

 each movement? 



