CHAP. II. THEIK INTELLIGENCE. 83 



5 had been previously drawn in by tne- 

 base, for this part had been gnawed. Again,. 

 I collected a handful of petioles lying loose 

 on the ground close to some plugged-up bur- 

 rows, where the surface was thickly strewed 

 with other petioles which apparently had 

 never been touched by worms; and 14 out 

 of 47 (i.e. nearly one-third), after having 

 had their bases gnawed had been pushed 

 out of the burrows and were now lying on 

 the ground. From these several facts we may 

 conclude that worms draw in some petioles 

 of the ash by the base to serve as food, and 

 others by the tip to plug up the mouths of 

 their burrows in the most efficient manner. 



The petioles of Robinia pseudo-acacia vary 

 from 4 or 5 to nearly 12 inches in length; 

 they are thick close to the base before the 

 softer parts have rotted off, and taper much 

 towards the upper end. They are so flexible 

 that I have seen some few doubled up and 

 thus drawn into the burrows of worms. Un- 

 fortunately these petioles were not examined 

 until February, by which time the softer parts 

 had completely rotted off, so that it was im- 

 possible to ascertain whether worms had 



H 



