Recipe to spot a literal "<>"

I'm trying to figure out how to search for this header in a message:

Message-ID: <>

As far as I can tell, this header is frequently present in spam, and
absolutely never present in anything else -- it is a bogus header.  
Unfortunately, the symbols \< and \> have special meaning to Procmail,
and I can't figure out how to escape > and < and make them literals.

Suggestions?  



--
Catherine Hampton <ariel(_at_)tempest(_dot_)boxmail(_dot_)com>