274 



ENTOMOLOGY 



FIG. 267. 



The ant-trees (Cecropia adenopus) of Brazil and Central 

 America have often been referred to by travelers. When 

 one of these trees is handled roughly, hosts of ants rush out 



from small openings in the 

 stems and pugnaciously at- 

 tack the disturber. Just 

 above the insertion of each 

 leaf is a small pit (Fig. 265, 

 a f b) where the wall is so 

 thin as to form a mere dia- 

 phragm, through which an 

 ant (probably a fertilized 

 female) bores and reaches a 

 hollow internode. To es- 

 tablish communication be- 

 tween the internodal cham- 

 bers, the ants bore through 

 the intervening septa (Fig. 

 266). They seldom leave 

 the Cecropia plant, unless 

 disturbed, and even keep 

 herds of aphids in their 

 abode. The base of each 

 petiole bears (Fig. 267) tender little egg-like bodies (" Miil- 

 ler's bodies") which the ants detach, store away and eat; 

 the' presence of these bodies is a sure sign that the tree is un- 

 inhabited by these ants, which, by the way, belong to the genus 

 Aztcca. 



It is too much to assert that the ants protect the Cecropia 

 plant in return for the food and shelter which they obtain. 

 All ants are hostile to all other species of ants, with few excep- 

 tions, and even to other colonies of their own species; so that 

 their assaults upon leaf-cutting ants are by no means special 

 and adaptive in their nature, and any protection that a plant 

 derives thereby is merely incidental. Furthermore, hollow 

 stems, glandular petioles and pitted stems are of common oc- 



Cecropia adenopus. Base of petiole showing 

 " Mullet's bodies." Slightly reduced. 



