strange type name in information_schema

Hi !

I'm running "PostgreSQL 9.0.2, compiled by Visual C++ build 1500, 32-bit".

I'm trying to get type information on functions out of information_schema.
When there is an array as input or output of a function I try to query
information_schema of the array type.

In this case udt_name gives the type name _text why does it not give text ?

Is this the right way to query the parameter types ?

CREATE OR REPLACE FUNCTION test(ta text[]) RETURNS void AS $$
BEGIN
RETURN;
END;
$$ LANGUAGE plpgsql;

select p.udt_name,p.data_type,*
from information_schema.routines r ,information_schema.parameters p
where r.routine_name = 'test'
and p.specific_name = r.specific_name
and p.specific_catalog=r.specific_catalog
and p.specific_schema=r.specific_schema

Best Regards
Dan S