284 TROPICAL NATURE Il 
are always accompanied by flocks of insectivorous birds, who 
prey upon the winged insects that are continually trying to 
escape from the ants. They even attack wasps’ nests, which 
they cut to pieces and then drag out the larve. They bite 
and sting severely, and the traveller who accidentally steps 
into a horde of them will soon be overrun, and must make 
his escape as quickly as possible. They do not confine them- 
selves to the ground, but swarm up bushes and low trees, 
hunting every branch, and clearing them of all insect life. 
Sometimes a band will enter a house, like the driver ants in 
Africa, and clear it of cockroaches, spiders, centipedes, and 
other insects. They seem to have no permanent abode, and to 
be ever wandering about in search of prey, but they make 
temporary habitations in hollow trees or other suitable places. 
Perhaps the most extraordinary of all ants are the blind 
species of Eciton discovered by Mr. Bates, which construct a 
covered way or tunnel as they march along. On coming 
near a rotten log, or any other favourable hunting ground, 
they pour into all its crevices in search of booty, their 
covered way serving as a protection to retire to in case of 
danger. These creatures, of which two species are known, 
are absolutely without eyes; and it seems almost impossible 
to imagine that the loss of so important a sense-organ can be 
otherwise than injurious to them. Yet on the theory of 
natural selection the successive variations by which the eyes 
were reduced and ultimately lost must all have been useful. 
It is true they do manage to exist without eyes; but that is 
probably because, as sight became more and more imperfect, 
new instincts or new protective modifications were developed 
to supply its place, and this does not in any way account for 
so widespread and invaluable a sense having become per- 
manently lost, in creatures which still roam about and hunt 
for prey very much as do their fellows who can see. 
Special Relations between Ants and Vegetation 
Attention has recently been called to the very remarkable 
relations existing between some trees and shrubs and the ants 
which dwell upon them. In the Malay islands are several 
curious shrubs belonging to the Cinchonacew, which grow 
parasitically on other trees, and whose swollen stems are 
