352 ANIMALS OF EGA. Chai>. V. 



worker-minors perform ; and again, in others (E. erra- 

 tica and E. vastator), the difference is so great that the 

 distinction of classes becomes complete, one acting the 

 part of soldiers, and the other that of workers * The 

 peculiar feature in the habits of the Eciton genus is 

 their hunting for prey in regular bodies, or armies. It 

 is this which chiefly distinguishes them from the genus 

 of common red stinging-ants (Myrmica), several species 

 of which inhabit England, whose habit is to search for 

 food in the usual irregular manner. All the Ecitons 

 hunt in large organised bodies ; but almost every 

 species has its own special manner of hunting. 



Eciton rapax. — One of the foragers, Eciton rapax, 

 the giant of its genus, whose worker-majors are half-an- 

 inch in length, hunts in single file through the forest. 

 There is no division into classes amongst its workers, 

 although the difference in size is very great, some being 

 scarcely one-half the length of others. The head and 

 jaws, however, are always of the same shape, and a 

 gradation in size is presented from the largest to the 



* There is one numerous genus of South American ants in which 

 the two classes of workers are nearly always sharply defined in struc- 

 ture, not only the head, but other parts of the body, being strikingly 

 different. This is the genus Cryptocerus, of which I found fifteen 

 species, but in no case was able to discover the distinctive function of 

 the worker-major class. The contrast between the two classes reaches 

 its acme in C. discocephalus, whose worker-majors have a strange dish- 

 shaped expansion on the crown of the head. All the species inhabit 

 hollow twigs or branches of trees, the monstrous-headed individuals 

 being always found quiescent and mixed with crowds of worker-minors. 

 It cannot be considered wonderful that the function of worker-majors 

 has not been discovered in exotic ants, when Huber, who devoted a 

 life-time to the study of European ants, was unable to detect it in a 

 common species, the Formica rufescens. 



