_Wars._--As with ants, so with bees, the great cause of war is plunder; and facts now well substantiated by numberless observers concerning 'robber-bees' indicate a large measure of intelligence. These aim at lessening their labour in collecting honey by plundering the store of other hives. The robberies may be conducted singly or in concert. When the thieving propensity is developed only in individual cases, the thieves cannot rely on force in plundering a foreign state, and so resort to cautious stealth. 'They show by their whole behaviour--creeping into the hive with careful vigilance--that they are perfectly conscious of their bad conduct; whereas the workers belonging to the hive fly in quickly and openly, and in full consciousness of their right.' If such solitary burglars are successful in obtaining plunder, their bad example leads other members of their own community to imitate them; thus it is that the whole bee-nation may develop marauding habits, and when they do this they act in concert to rob by force. In this case an army of bees precipitates itself upon the foreign hive, a battle ensues, and if successful in overcoming resistance, the invaders first of all search out the queen-bee and put her to death, whereby they disorganise their enemies and plunder the hive with ease. It is observed that when this policy is once successful, the spirit of aggrandisement is encouraged, so that the robber-bees 'find more pleasure in robbery than in their own work, and become at last formidable robber-states.' When an invaded hive is fairly overcome by the invaders killing the queen, the owners of the hive, finding that all is lost, not only abandon further resistance, but very often reverse their policy and join the ranks of their conquerors. They assist in the tearing down of their cells, and in the conveyance of the honey to the hive of their invaders. 'When the assailed hive is emptied, the next ones are attacked, and if no effective resistance is offered, are robbed in similar fashion, so that in this way a whole bee-stand may be gradually destroyed.' Siebold observed the same facts in the case of wasps (_Polistes gallica_). If, however, the battle turns in favour of the defenders, they pursue the flying legions of their enemies to a distance from their home. It sometimes happens that the plundered hive offers no resistance at all, owing to the robbers having visited the same flowers as the robbed, and so probably (having much the same smell) not being recognised as belonging to a different community. The thieves, when they find such to be the case, may become so bold as to stop the bees that are returning to the hive with their loads, of which they deprive them at the entrance of the hive. This is done by a process which one observer, Weygandt,[56] calls 'milking,' and it seems that the milking bee attains the double advantage of securing the honey from the milked one and disarming suspicion of the other bees by