I think the diagnosis of varroa for what was described may be too hasty.  My
initial call was that it may be similar to the discussion of the white spot on
bees' thorax attributed to pollen which the bees are not able to wipe off.
Don't recall when the discussion took place and have not had the time to search
the archives.

The quick shooting diagnosis of varroa overlooks the fact that varroa are most
often found between that plates of bees' abdomens.

I'm not ruling out varroa, but I think the diagnosis is too quick, too easy for
a condition that was not well described.  What say you preacher man?