Well, gave my dad a call... first he said T.M. better gain some respect or he will eat trough a straw for weeks, second he gave me this:
Someone who studies beetles is a Coleopterist! Thanks dad!
And the difference between bugs and beetles is that 'bug' is a common name for just about anything dime-sized and walking on more then four legs (mostly used by the lesser respectful and ignorant among us) and 'beetle' refers to a particular group of insects in a more scientific manner. For the full answer (and this is from my own bare brain, no googling included): beetles; insects in a great variety of sizes, fitted with 2 sets of wings, from which the front pair has evolved to a hard leathery shell. The back wings are or folded beside each-other below the armored front wings, or are rendered tiny and useless, in the last case the shell wings are stuck to the back-body as an permanent shield and the insect is unable to fly.
Furthermore, beetles specify themselves by having biting, pincer-like mouth-parts. They can be herbi- carni- and omnivorous. They feed more on tissue compared to most other insects, who rely more on fluids alone (except hive-based predators like ants and wasps).
Their durability and adaptation has led the beetle to be the one insect who has conquered more types of environment than any other. Beetles can be excellent fliers, swimmers and runners and can be found in the heat of the desert as-well as in deep water.