116 ANIMAL INTELLIGENCE. 



down the outsides of the column, they every now and 

 again stop to touch antennae with some member of the 

 rank and file, as if to give instructions. When the scouts 

 discover a wasp's nest in a tree, a strong force is sent out 

 from the main army, the nest is pulled to pieces, and all 

 the larvae carried to the rear of the army, while the wasps 

 fly around defenceless against the invading multitude. 

 Or, if the nest of any other species of ant is found, a 

 similarly strong force, or perhaps the whole army is de- 

 flected towards it, and with the utmost energy the innu- 

 merable insects set to work to sink shafts and dig mines 

 till the whole nest is rifled of its contents. In these 

 mining operations the ants work with an extraordinary 

 display of organized co-operation ; for those low down in 

 the shafts do not lose time by carrying up the earth which 

 they excavate, but pass on the pellets to those above ; and 

 the ants on the surface, when they receive the pellets, 

 carry them, ' with an appearance of forethought that quite 

 staggered ' Mr. Bates, only just far enough to ensure that 

 they shall not roll back again into the shaft, and, afte^ 

 depositing them, immediately hurry back for more. 

 But there is not a rigid division of labour, although the 

 work ' seems to be performed by intelligent co-operation 

 amongst a host of eager little creatures ; ' for some of 

 them act ' sometimes as carriers of pellets, and at another 

 as miners, and all shortly afterwards assume the office ot 

 conveyors of the spoil.' Again, as showing the instincts 

 of co-operation, the following may also be quoted from 

 Bates's account : 



On the following morning no trace of ants could be found 

 near the place where I had seen them the preceding day, nor 

 were there signs of insects of any description in the thicket ; 

 but at the distance of eighty or one hundred yards, I came 

 upon the same army, engaged evidently on a razzia of a similar 

 kind to that of the previous evening; but requiring other re- 

 sources of their instinct, owing to the nature of the ground. 

 They were eagerly occupied on the face of an inclined bank of 

 light earth in excavating mines, whence, from a depth of eight 

 or ten inches, they were extracting the bodies of a bulky species 

 of ant of the genus Formica. It was curious to see them crowd- 

 ing round the orifices of the mines, some assisting their com 



