THE MYSTERY OF THE SWARM 187 



renders her so heavy and bulky that often she can 

 scarcely get on the wing. The object of this is 

 that she may be all the more ready for laying 

 when the new home is established. It is also 

 well ascertained that all swarming bees have their 

 honey-sacs well filled, and this loading up for the 

 journey takes place just before the signal for 

 departure is given. There is great variation in 

 the behaviour of the different stocks in a bee- 

 garden during the swarming season, and many 

 close observers are unable to detect any sure signs 

 that a particular hive is going to swarm. But it 

 appears fairly well established that, when a swarm 

 is imminent, nearly all the bees of that stock 

 remain at home, even when all other hives in the 

 garden are in full foraging activity. Such a hive 

 gives out a peculiar throbbing note, which suggests 

 the noise made by a powerful locomotive brought 

 to a standstill, but with full steam up, and impatient 

 to be gone. Just before the issue of the swarm 

 there is often a curious lull in this pent-up, forceful 

 sound, and probably this is the moment when the 

 travellers are lading themselves up for the march. 

 Immediately after — and here it is difficult not to 

 believe that a definite, authoritative signal for the 

 movement is given — a sudden stir and tumult 

 begins in the centre of the crowded hive, much 

 like that caused by a heavy stone cast into water. 

 This radiates swiftly in all directions until it 

 reaches the bees near the entrance, and then the 



