Can't find module that exists

From the cli I enter the python shell via python.

I then take a look at my import search path:

import sys
print 'n'.join(sys.path)

/path/to/a/package/foo.bar
/other paths...

So I know foo.bar is in my python search path.

Continuing inside the python shell:

import imp
imp.find_module('foo.bar')

ImportError: No module named foo.bar

Hmm, the sys.path tells me that foo.bar is on the python search path, but the imp module can't seem to find it.

Continuing further inside the python shell:

from foo.bar import baz
baz

<module 'foo.bar.baz' from '/path/to/a/package/foo.bar/foo/bar/baz.pyc'>

Yes, I have directories foo and bar under my main directory foo.bar. Why would imp.find_module not be able to locate my package?