Question on string value expression wildcarding

I have LIKE expressions:
(a)    name LIKE 'kp.dhs.%'       (b)     name LIKE 'kp.dhs%'

where the name column contains strings prefixed with "kp.dhs.".

I'm using postgresql  7.0.2.

Expression (a) fails to match any names while (b) matches
all strings prefixed with "kp.dhs", including (as expected)
those prefixed with "kp.dhs.".

So I take it that ".%" has some special meaning in wildcarding,
but my (limited) SQL references don't mention this case.
Is this To Be Expected SQL behavior?  If so, what
expression can be used to match only strings prefixed with
"kp.dhs."?

Thanks!
--
Steve Wampler-  SOLIS Project, National Solar Observatory
swampler@noao.edu