Cockroaches do not usually bite, (only in extremely rare cases) as human skin provides no nutrition for cockroaches. It's often the nasty allergic reactions to cockroaches that are thought of as a...
Small and white.
It looks like black pepper. Like if you accidentally spilled some from your pepper shaker. Very small and black.
an image of cockroach (Cockroaches, insects of the order Blattaria or Blattodea) (image: Cockroachcloseup.jpg)
You can see its egg sac sticking out of the back end of it. See the Related Link.