Group and Role Disagreement

Fellow Hackers,

Given this SQL:
   BEGIN;
   CREATE ROLE foo WITH NOLOGIN;
   CREATE ROLE foo_bar WITH LOGIN PASSWORD '***' INHERIT IN ROLE foo;
   CREATE ROLE foo_baz WITH LOGIN PASSWORD '***' INHERIT IN ROLE foo;
   CREATE ROLE foo_yow WITH LOGIN PASSWORD '***' INHERIT       IN ROLE foo, foo_bar, foo_baz;

   SELECT groname, array_agg(rolname)     FROM pg_group     JOIN pg_roles ON pg_roles.oid = ANY(grolist)   WHERE
gronameIN ('foo', 'foo_bar', 'foo_baz', 'foo_yow')   GROUP BY groname; 
   SELECT r.rolname,     ARRAY(SELECT b.rolname           FROM pg_catalog.pg_auth_members m           JOIN
pg_catalog.pg_rolesb ON (m.roleid = b.oid)           WHERE m.member = r.oid) as memberof   FROM pg_catalog.pg_roles r
WHERErolname IN ('foo', 'foo_bar', 'foo_baz', 'foo_yow'); 
   ROLLBACK;

The output is:
   BEGIN   CREATE ROLE   CREATE ROLE   CREATE ROLE   CREATE ROLE    groname |         array_agg
---------+---------------------------   foo     | {foo_bar,foo_baz,foo_yow}   (1 row) 
    rolname |       memberof           ---------+-----------------------    foo     | {}    foo_bar | {foo}    foo_baz
|{foo}    foo_yow | {foo,foo_bar,foo_baz}   (4 rows) 
   ROLLBACK

My question is: why is the group membership of the foo_bar, foo_baz, and foo_yow roles not reflected in pg_group?
Shouldit not have the same associations as pg_roles? A quick query shows that the only record in pg_group is for the
"foo"group -- it doesn't even know that the foo_bar, foo_baz, and foo_yow roles also act as groups. Should it? 

Thanks,

David