This is called a Serra-Pau, which I believe is Portuguese for a variety of longhorn beetle. But don't quote me. Maybe a Brazilian etomologist can clear this up.
I've never thought to look a longhorn beetle in the mouth, but now that I have, I'm surprised. I've come to expect nasty mandibles and articulated parts in my insects. But the innards of this mouth almost look to be fleshy. Is that possible? I just assumed that it would be all chitin and hardness, but I guess insects are allowed to have soft spots too. That might almost be endearing, if it didn't involve a part that wanted to eat me. Source