356 ANIMALS OF NEIGHBOURHOOD OF EGA. Cuap. XII. 
of them a little difference amongst the workers regarding the size of the 
head ; but in some species (E. legionis) this is not sufficient to cause 
a separation into two classes, with division of labour; in others (E. 
hamata) the jaws are so monstrously lengthened in the worker-majors, 
that they are incapacitated from taking part in the labours which the 
worker-minors perform ; and again, in others (E. erratica 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 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. Thearmies of Eciton rapax are never very 
numerous. 
Lciton 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 
English red ant (Myrmica rubra), which it also resembles in colour. 
The Eciton legionis lives in open places, and was seen only on the 
sandy campos of Santarem. The movements of its hosts were, therefore, 
much more easy to observe than those of all other kinds which inhabit 
solely the densest thickets ; its sting and bite also were less formidable 
than those of other species. The armies of E. legionis consist of many 
thousands of individuals, and move in rather broad columns. ‘They are 
just as quick to break line on being disturbed, and attack hurriedly and 
furiously any intruding object, as the other Ecitons. ‘The species is not 
a common one, and I seldom had good opportunities of watching its 
* 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 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 it 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. 
