Tim Watts wrote:
While we're on the subject:

When I was clearing hardcore out of the garden yesterday, I pulled a lump of
concrete out of the ground and there was a little tiny papery nest -
smaller than a tennis ball and several waspy things (about 2cm long)
wibbling around it. Needless to say, they got a spade of earth dumped on
them sharpish.

Where they wasps or something else? Didn't realise wasps lived
underground?...

What we used to call German wasps (big with yellow and black stripes) certainly
make their nests underground. I recall big excitement as a kid when a nest was
dug up, after being well doused with something nasty. If I recall correctly it
was 30-40 cm across.

Introduced wasps are now considered a major pest in the NZ bush, because they
get all the caterpillars that some birds prey on.