Flávio, não sei se tem facebook..mas tem uma comunidade chamada entomologia Brasileira...eu coloquei algumas fotos lá e rapidamente alguém indicou uma possível identificação. Espero ter ajudado. Júlio.
if you need help from another specialists, please be correct and don't waste our time.
First of all, you have not provided any locality information on your specimens. There are more than 86 000 (!!!) species of the Curculionidae across the globe. Don't expect there is any "superhero" familiar with all of them. Please provide locality data for your specimens.
Second, identification of insects usually requires high resolution and good magnification microscopes, dissection of genitalia etc. Your photographs are so basic - perhaps it will be possible for the specialist to identify genus (subfamily for sure), but certainly not the species.
Dear Flavio, you could to contact with Nikolai Yunakov. He is a specialist on Curculionidae and he is here on Rg. But, please, write area and localities of this specimens.