(urth) do the Hierogrammates *care* about the megatherians?

[James Wynn]

I can't find anything determinate on this. Does anyone else? I've missed 
this particular question being discussed.

Lee thinks they are working in concert and others wonder how a flood 
would get rid of them.
Analogizing with the inhumi in 'The Book of the Short Sun' and the Storm 
King in 'An Evil Guest', I suspect that getting rid of the Megatherians 
is irrelevant to the plan for the Rise of the Heiros. They are plagues 
of opportunity. They prey on our moral weakness. Not our physical or 
technological weaknesses.

But can someone help me identify all the places that the Heiro-beings 
discuss the Megatherians?

J