470 



ANIMALS OF EGA 



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 organized 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, how- 

 ever, are always of the same shape, and a gradation in 

 size is presented from the largest^to the smallest, so that 

 all are able to take part in the common labours of the 

 colony. The chief employment of the species seems to 

 be plundering the nests of a large and defenceless ant of 

 another genus (Formica), whose mangled bodies I have 

 often seen in their possession, as they were marching 

 away. The armies of Eciton rapax are never very 

 numerous. 



Eciton legionis. — Another species, E. legionis, agrees 

 with E. rapax in having workers not rigidly divisible 

 into two classes ; but it is much smaller in size, not 

 differing greatly, in this respect, from our common 



^ There is one numerous genus of South American ants 

 in which the two classes of workers are nearly always sharply 

 defined in structure, not only the head, but other parts of the 

 body, being strikingly difierent. 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 lifetime to the study of 

 European ants, was unable to detect it in a common species, 

 the Formica rufescens. 



