THE BUTTERFLY AND ITS ALLIES 37 



so modified to aid it in capturing slaves that it is absolutely dependent 

 upon its slaves for food, and it would die surrounded by food were 

 none of its slaves at hand to feed it. 



The Agricultural Ant. One of our most interesting ants is the 

 Agricultural Ant of Texas (Myrmica l molefaciens 2 ). This ant makes 

 a circular clearing about its mound, upon which it allows only one 

 species of grass to grow. Indeed, some observers maintain that the 

 seed of this grass is planted upon the clearing 

 by the ants. Certain it is that the ripe seeds 

 of the grass are carefully harvested by the ants 

 and stored within the chambers of their mound. 

 From time to time the seeds are brought out and 

 dried to prevent sprouting. During rainy sea- 

 sons, when the seeds germinate despite all pre- 

 cautions, the ants are said to nip off the sprout 

 upon its first appearance. 



The army ants, of which there are several 

 species, occur in great numbers in tropical South 

 America. Like many other species which live 

 by hunting, they migrate from a locality after 

 having exhausted it of their food. While on 

 the inarch, the young of the species are trans- 

 ported by some of the adults. When an army 

 of these ants approaches a place, every living 

 animal endeavors to escape. The breeding birds 



must be on the alert to pick off the advance Fl , a W.Pimplapeda- 



hs, a parasite on the 



guard to prevent them from returning to the caterpillar of Clisio- 

 ar my with news of the presence of nestlings. campa. Upper figure 

 Insects of all sorts, young and old, fall a ready 

 prey to these swarms. Some spiders escape by 

 suspending themselves by their threads, and insects which resemble 

 leaves often find safety in keeping rigidly still. When an army of 

 these ants enters a house, the inhabitants find it wisest to leave 

 the invaders in possession, for in a few hours the house is cleared 

 of every living thing moths, cockroaches, rats, mice, all have fled 

 or been devoured. 



The leaf -cutting ants are another tropical American species. The 



, ant. 2 Mole or mound builder. 



