352 
ANIMALS OF EGA. 
Chap. Y. 
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. 
