Remarkable Case of Instinct 19 
I noticed that spiders were generally most intelligent in 
escaping, and did not, like the cockroaches and other insects, 
take shelter in the first hiding-place they found, only to be 
driven ‘out again, or perhaps caught by the advancing army 
of ants. I have often seen large spiders making off many 
yards'in advance, and apparently determined to put a good 
distance between themselves and their foe. I once saw one 
of the false spiders, or harvest-men (Phalangide), standing in 
the midst of an army of ants, and with the greatest circum- 
spection and coolness lifting, one after the other, its long legs, 
which supported its body above their reach. Sometimes as 
many as five out of its eight legs would be lifted at once, and 
whenever an ant approached one of those on which it stood, 
there was always a clear space within reach to put down 
another, so as to be able to hold up the threatened one out of 
danger. 
I was much more surprised with the behaviour of a green, 
leaf-like locust. This insect stood immovably amongst a 
host of ants, many of which ran over its legs, without ever 
discovering there was food within their reach. So fixed was 
its instinctive knowledge that its safety depended on its 
immovability, that it allowed me to pick it up and replace it 
amongst the ants without making a single effort to escape. 
This species closely resembles a green leaf, and the other 
senses, which in the Ecitons appear to be more acute than 
that of sight, must have been completely deceived. It 
might easily have escaped from the ants by using its wings, 
but it would only have fallen into as great a danger, for the 
numerous birds that accompany the army ants are ever on 
the outlook for any insect that may fly up, and the heavy 
flying locusts, grasshoppers, and cockroaches have no chance 
of escape. Several species of ant-thrushes always accompany 
the army ants in the forest. They do not, however, feed on 
the ants, but on the insects they disturb. Besides the ant- 
thrushes, trogons, creepers, and a variety of other birds, are 
often seen on the branches of trees above where.an ant army 
is foraging below, pursuing and catching the insects that 
fly up. 
The insects caught by the ants are dismembered, and their 
too bulky bodies bitten to pieces and carried off to the rear. 
Behind the army there are always small columns engaged on 
B 
