THE SOCIAL INSECTS 



was supplied and a larger wasp would be produced. But this 

 would only put the problem one step back, since we should 

 want to know why the grubs in the large cells took longer to 

 mature. Janet's records for the hornet show that the develop- 

 mental period is longer in the early part of the season, but 

 there is nothing to show that queens develop more slowly 

 than the workers which are being reared at the same time. 



In the honey bee the queen, although larger than the 

 worker, develops more rapidly, probably because of the 

 richer food she is given as a grub. On the whole, the evidence 

 in wasps suggests that the important thing is likely to be 

 some change in the behaviour or physiology of the old 

 queen rather than a change in the food supplied to the 

 grubs. Common wasps and hornets are the only social 

 wasps in which the queen-cells are easily recognisable ; in 

 the others cell size is almost uniform. 



When the young queens emerge from their cocoons they 

 mature in a few days and leave the nest rather rapidly. Pair- 

 ing takes place in the open, probably as often with males 

 from other colonies as with their brothers. Very soon after 

 pairing the young queens enter hibernation. Meanwhile, the 

 social organisation of the colony degenerates. At this stage 

 the workers may kill many of the remaining grubs, either 

 flying out with them and throwing them away, or using them 

 as food for the others, or even eating them themselves. No 

 convincing explanation of this behaviour can at present be 

 given, but from Deleurance's experiments on Polistes it may 

 turn out to be associated with a glandular degeneration of 

 the old workers. The failure of the nurses seems sometimes 

 to be associated with the exhaustion of the ovaries of the 

 old queen or with her death, but it may also occur in nests 

 where she survives. The final end of the colony is usually 

 determined by the onset of cold weather, a few sleepy 



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