318 



Introduction to Botany. 



ing the pieces to their nests for the purpose of working 

 them into a pulp which they plant with a certain kind of 

 fungus, constituting their chief or sole food. Figure 166 



shows the way in which 

 these ants destroy the 

 leaves. 



The soldier ants that 

 protect the Cecropias 

 against the leaf-cutting 

 species do not, however, 

 serve without pay, for 

 these trees provide 

 them with both food 

 and shelter. The Ce- 

 cropia branches are hol- 

 low at the center, the 

 cavity being divided by 

 numerous cross parti- 

 tions (Fig 167, A). Just 

 above the axils of the 

 leaves are thin places 

 (Fig. 167 B, a) in the 

 stem where the tissues 

 are lacking in woody 

 elements and are easily 

 cut through by the ants. The ants also find no difficulty 

 in perforating the cross partitions so that they can pass 

 from chamber to chamber. The food provided for the 

 ants is produced at the bases and under sides of the 

 petioles in the form of minute egg-shaped bodies, rich in 

 proteids and fats. These bodies are renewed as often 

 as the ants remove and carry them to their nests (see 

 Fig. 168). 



FIG. 166. 



f, leaf-cutting ants walking off with their plun- 

 der; K, a leaf showing damage from leaf-cut- 

 ting ants. After A. MOLLER. 



