A Big Huge Beetle That Is Half A Butterfly

There's a funny insect that doesn't often spy.
It isn't quite a harry grub or it isn't quite a spy. It is something like a spider and a little like a bee. But nothing like a irritating fly, that fly's upon a woolly tree. When you first come upon it will give you quite a scare! But when you look for it again you find it isn't there. This is just a funny joke of mine, so please forgive me fine. There is nothing that a BiG Huge Beetle that is half a Butterfly!