These sound like like the things I always knew as harvest mites and
they don't seem to be very common in the UK now, though they used
to be apparently (hence the name). Looking it up in the
dictionary - says that they are the same thing and are also called
chigoe's and chigre's though the same term also covers the African
and Asian flea Tunga penetrans, a species where the gravid female
burrows into the skin, usually under the toe nails:-) The harvest
mite is Trombicula and it's the larva which burrows into the skin.
A good long soak in the bath seems to be the most popular remedy
(and they sure do itch:-))
Regards, Adrian Arnold.