THE PLANT WORI^D 103 



God grant that there be some way to arrange it, for we are sorely 

 troubled ! ' ' 



Saturday, Septeynber 16. — The Governor visited Agaiia to-day, and I 

 reported to him the result of his last general order, " It is a very simple 

 matter," he said; " we will grant them divorces." " Who will grant 

 them, sir, ' ' I asked. ' ' Why, you, ' ' he said ; " if you do not wish to assume 

 the responsibility, just add to the decree, 'by order of the Governor.' " 



[to be continued.] 



Plants that Keep a Body-Guard. 



By Frederick Le Roy Sargent. 



One of the most serious difficulties encountered by those who culti- 

 vate plants in the tropics comes from the depredations of leaf-cutting 

 ants. These little creatures march in armies, thousands strong, and on 

 coming to a plant that suits them, they ascend it and spread to every 

 leaf. Each ant now snips off with his sharp jaws a piece of leaf bigger 

 than himself, and swinging it over his head, joins a procession of his 

 fellows similarly laden and bound for the nest. New ones come to take 

 their place, and in a short time not a leaf remains. 



It is found that native plants suffer much less than those introduced 

 from other regions, and this is because the indigenous sorts are mostly 

 provided with some means of keeping off the leaf -cutters. Thus the 

 stems are sometimes slippery, or sticky, or covered with hairs over which 

 the ants can not climb, but the most efficient means is the keeping of a 

 standing army to resist the invaders. 



One of the best examples of this remarkable method of defense is 

 afforded by a species of acacia, known as the " bull's-horn thorn-tree," 

 which is a native of Nicaragua. The name is descriptive of a pair of 

 horn-like thorns situated at the base of each compound leaf. All but 

 the youngest thorns are found to be hollow and inhabited by colonies of 

 ants. These are smaller than the leaf -cutters, but better fighters, and 

 fiercely resist any encroachments on their domains. They sting severely, 

 so that even the higher animals have much to fear from them. 



As fast as the thorns become large enough for occupancy, the ants 

 bore into one of a pair and proceed to hollow it out by eating the sweetish 

 pulp within, leaving the hardened wall. They bore through the parti- 

 tion which separates the thorns at the base and so continue the cavity 

 into the other thorn. In this way one entrance is made to answer for 



