Hi, 

This appears to be an Oriental Beetle in the second photo and it might be what chewed petals in the first photo, but we can't be certain.

Clematis typically do not get seriously damaged or defoliated by leaf-chewing insects so treatment should not be needed; if necessary, though, you can knock them off by hand or by treating foliage with spinosad for the least amount of chemicals possible that could harm other pollinators.  Just be cautious not to get residues on the blooms or they could harm bees until it is dried.

Let us know if you have further questions with it.