The bug is known as cuban may beetle. They start off as giant ugly looking grubs that feed on grass roots. Twice a year you will see them, once in may and once in sept if memory serves. They can be a real problem -- even to the point of totally defoliating a tree that they are fond of. They tend to like plants in the sapoticaceous family.
But they are easy to get rid of: just delete your grass and after about 18 months, they will be gone. Oddly they don't travel very far, so even though your neighbors have grass, you can effectively eliminate the problem by just mulching over your lawn. That's what I did. Haven't seen them in years.
There are also grub control products that you can use. Milky spore could help? I haven't tried either though.