70 ANIMAL INTELLIGENCE. 



hand over their booty to the slaves, and trouble themselves no 

 more about it. A few days afterwards the stolen pupae or 

 nymphse emerge, without memory of their childhood, and imme- 

 diately and without compulsion take part in all tasks. 



According to Biiclmer's account, 1 



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 unknown to them. Forel several times saw 

 the army completely lose its way- an incident only once ob- 

 served 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 return- 

 ing 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 hun- 

 dred 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 prevented th^ir 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 neighbourhood, they do not 

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

 road during their aimless wanderings about, and recognise and 



1 Gcirtesleben der Thiere, pp. 115-9. 



