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 Buchner’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 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 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 Geistesleben dev Thieve , pp. 145-9. 
