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 exsectce 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 exsectw, 

 three or four of them seizing an opponent and pulling off his 

 legs. In similar fashion the attack of the Lasius species is 



