I was gonna say, it looks like a weevil. I opened a pack of icing sugar once to find loads of them in there. If you ingest them, they can give you a bad tummy; I don't know if it would be worse for a baby, but I assume so. Make sure you don't store it in your cupboard, because once they get loose you will find them in any open packet of flour, icing, formula, powdered custard etc. If it's been in the cupboard already, you should go through the contents and make sure everything else is weevil free. I check all my baking ingredients as soon as I bring them home, and then store them in a massive tupperware now. At least then you know they won't get infested.
And as far as I'm aware, Cow & Gate and Aptamil are made in the same factory, but I can't be sure. It doesn't mean it's a bad product though, so don't boycott C&G because of it; it's most probably just a bad batch. You should definitely inform them, perhaps quoting the batch number on the pack.