VII MEP RACTING QUEENS 105 
Each domicile was prepared by cutting out a 
rectangular sod with a sharp spade; the floor of 
the excavation from which the sod was taken was 
levelled, and in the centre of it a small round 
cavity about 4-in. in diameter was made with a 
trowel. This cavity was to contain the nest. 
Next, a tunnel 1-in. in diameter and about 2 feet 
long, as a passage for the bees connecting the 
cavity with the surface of the ground, was made 
by driving through the eh a steel rod having 
\ \ 
x 
bile 
esl cavity 

Fic. 22.—Section of Sladen’s original device to attract underground-nesting 
humble-bees. 
a thickened and pointed head. The mouth of the 
tunnel had the grass close around it plucked short 
so that it might be easily noticed by the searching 
queens. Most of the nests were made of dead 
grass like those made in 1895, but some consisted 
of soft moss torn to pieces and rolled into a ball, 
and a few were made of tow which, after it had 
been deodorised by exposure to the weather for a 
few days, was cut up into lengths of about half-an- 
inch. The nest having been deposited in the 
cavity, a tile was placed over it, the sod was put 
back in its place over the tile, and the edges of the 
sod were stamped down. 
