ANTS AND ANT LIFE. 145 



X,espes, that the original leaders remain behind to keep order 

 in the rear, to guide it, and to inspire the laggards, while 

 others take the place at the head. From time to time the 

 army makes a short halt, partly to let the rearguard close 

 up, partly because different opinions arise as to the direction 

 of the host, or because the place at which they are is un- 

 known to them. Forel several times saw the army com- 

 pletely lose its way ajn incident only once observed by 

 Huber. Forel puts the number of warriors in such an army 

 at from one hundred to more than two thousand. Its speed 

 is on an average a metre per minute, but varies much 

 according to circumstances, and is naturally least when 

 returning laden with booty. If the distance be very great, 

 such bodily fatigue may at last be felt that the whole attack 

 on the hostile nest is given up, and a retreat is begun ; 

 Forel once saw this happen after they had passed over a 

 distance of two hundred and forty yards. Sometimes it 

 seems as though, on coming within sight of the hostile nest, 

 a kind of discouragement took possession of them, and pre- 

 vented their making the attack. If the nest cannot at once 

 be found, the whole army halts, and some divisions are sent 

 forward to search for it, and these are gradually seen 

 returning towards the centre. Forel also saw such an army 

 only searching the first day, advancing zigzag, and with 

 frequent halts, whereas on the following day it went forward 

 to its aim swiftly and without delay, having found out the 

 road. It seems that a single ant, even if it knows the 

 way and the place, is not able alone to lead a large army, 

 but that a considerable number must be employed in this 

 duty. Mistakes as to the road occur with special ease during 

 the return journey, because the several ants are laden with 

 booty and cannot readily understand each other. Individual 

 ants are then seen to wander about in every direction often 

 for a long time, until they at last reach a spot known to 

 them, and then advance swiftly to their goal. Many never 

 come back at all. These mistakes easily occur when the 

 robbers which have passed into a hostile nest do not come out 

 again at the same holes whereby they entered, but by others 

 at some distance, for instance by a subterranean canal. 

 Coming out thus in a strange neighborhood they do not 

 know which way to take, and only some chance on the right 

 road during their aimless wanderings about, and recognise 



