50 OUR INSECT FRIENDS AND FOES 



The Ecitons or Foraging Ants, the Taucas oi 

 the Indians of Brazil, are carnivorous, hunting 

 their prey in large and well-organized armies. 

 The communities consist of males, females, and 

 two types of workers large-headed majors and 

 small-headed minors. In the small-headed or 

 minor workers the jaws are always of the ordi- 

 nary shape, but in some species the jaws of 

 the large-headed major workers are so greatly 

 lengthened as to make it quite impossible for 

 them to take part in the labours of their small- 

 headed companions. Ten species of these 

 Foraging Ants were observed and described by 

 Bates during his wanderings in tropical South 

 America, and he found that nearly every species 

 had its own particular method of marching ; 

 some, like the giant Eciton rapax, which chiefly 

 preys upon a large but defenceless Formica Ant, 

 hunting in single file through the forests ; others, 

 like the smaller and more numerous Eciton 

 legionis, marching alone in fairly broad columns 

 numbering many thousand individuals ; others, 

 again, the blind Ecitons, push forward step by 

 step under covered ways which they construct 

 as they advance. There are two interesting 

 transitional species connecting those Ecitons 

 which are provided with visual organs to those 

 that are absolutely blind. In the first transi- 

 tional species, Eciton crassicornis, the eyes are 

 sunk in rather deep sockets, and the insect 

 habitually shuns the light when on its 

 foraging expeditions, moving along under fallen 

 leaves, and when compelled to cross a cleared 

 space, the workers construct a temporary covered 



