Firstly, both crowdsourcing and co-creation involve an ingredient of collaboration, however while crowdsourcing is seeking information and ideas from a group of people, co-creation seeks information and ideas from with a groups of people.
Further, co-creation is different in that the group works together on one concept.
Co-creation typically has smaller more specialized groups that capture ideas from many and work them through different stages to develop it.
So while crowdsourcing is focused on “quantity” of ideas or thoughts, co-creation is more focused on the “quality” of ideas that has being generated or discussed.
Here is a great article that summaries the same: http://dailycrowdsource.com/crowdsourcing/articles/opinions-discussion/559-cr…