Bryn - it's "most".
An anthology (ed Young and Jackson Maclow), which I guess should be viewed as the primary source, presents it as follows:-
most of them
were very old grasshoppers
It's been misquoted for years, hence (presumably) the confusion.
Ah, thanks for that, autoh. I was a little frustrated that Bryn's original question seemed so specifically directed at people who'd already know what he was talking about that he didn't even provide the whole quotation, but you've said enough to enable me more or less to work it out for myself.
One more question I'd be interested to know the answer to: When was this
Anthology published? I hadn't realised Jackson MacLow had collaborated with Young; I thought of him as a much more recent phenomenon (probably because I first discovered him in connection with Ferneyhough ...).
Added Brownie points for any more information either of you might feel inclined to give beyond that. It does all sound very interesting.