SOLITARY BEES AND WASPS. 187 



room would soon have been full of young wasps, 

 much to the discomfort of the coming visitor. 



One of the mason wasps called Odynerus not 

 only makes a tunnel a few inches deep in the 

 ground, generally in sandy banks, but it builds 

 a kind of little tube of grains of sand glued 

 together and places it just over the hole. It 

 curves a little to one side, and is very possibly 

 intended to act as a protection against various flies 

 and parasites that would try to creep down and 

 lay their eggs amongst those of the wasp. 



This wasp stores up grey caterpillars for its 

 young as the mason bees do, so we see that they 

 have their use in tending to reduce the number of 

 larvae which prey upon our vegetables, and should 

 be protected on that account. 



An old silver-fir at the Grove, which had become 

 decayed in the centre, became a home for countless 

 thousands of a small species of wasp ; they scooped 

 it into endless galleries and cells, and filled them 

 with half-dead bluebottles and other flies to serve 

 as food for their grubs. 



I sat and watched them at work for half an hour 

 one day, and saw that about every half-minute 



