Bald Patches

I recently began taking in a neighborhood cat, feeding him and letting him in when it rains.
I notice that he has thining fur stripes from his ears to his eyes, indnical on either side. He's an all black cat, and I saw another cat on TV with the same thing. I wonder if this is normal or if he may be sick.
He does have fleas but no worms... what else might it be!?
Please help my Coal!

All cats have very thin hair in that area, so that is normal. But if this cat has been outside, he needs to be dewormed and checked for other parasites. If you are going to keep him, he also must be neutered.