78 
ANIMAL INTELLIGENCE. 
the opening either with its head or abdomen. The Campo- 
notus species also defend their nests by stretching their heads 
in front of the openings, drawing back the antennae. Each 
approaching enemy thus receives a sharp blow or bite delivered 
with the whole weight of the body. MacCook noticed in the nests 
of the soon to be described Pennsylvanian mound-building ants, 
the employment of special sentries, which lay watching within 
the nest entrances, and sprang out at the first sight of danger 
to attack the enemy ; and it was wonderful to see with what 
swiftness the news of such an alarm spread through the nest, 
and how the inhabitants came out en masse to meet the enemy. 
The Lasius species defend their large, strong, and very extensive 
nests against hostile attack or sieges with equal courage and 
skill, while other timid species seek to fly as speedily as possible 
with their larvae, pupae, and fruitful queens. There is, as Forel 
tells us, a regular barricade fight. Passage after passage is 
stopped and defended to the uttermost, so that the assailants 
can only advance step and step. Unless the latter are in an 
enormous majority, the struggle may last a very long time with 
these tactics. During this time, other workers are busy pre- 
paring subterranean passages backwards for eventual flight. 
Generally such passages are already made, and during a fight a 
new dome of the Lasius may be seen rising at a distance, it not 
being difficult for them to make this with the help of their ex- 
tended subterranean passages and communications. 
The F ’. exsecta or pressilabris fights in a peculiar way, which is 
due to care of their small and very tender bodies. It avoids all 
single combats, and always fights in closed ranks. Only when 
it thinks victory secure does it spring on its enemy’s back. But 
its chief strength lies in the fact that many together always 
attack a foe. They nail down their opponent by seizing its legs 
and holding them firmly to the ground, while a comrade springs 
on the back of the defenceless creature and tries to bite through 
its neck. But if threatened the holders sometimes take flight, 
and so it happens that in battles between the exsect ce and the 
much stronger pratenses not a few of the latter are seen running 
about with a small enemy clutching their shoulders, and making 
violent efforts to tear the neck of its foe. If the bearer is then 
seized with cramp, the nervous cord has been injured. On the 
other hand, if an exsecta is seized by the back by a pratensis it 
is at once lost. 
The tactics of the turf ants resemble those of the exsectce , 
three or four of them seizing an opponent and pulling off his 
legs. In similar fashion the attack of the Lasius species is 
