>>32160457As much as I do love galvantula probably replace it with scizor. It is good but with bug you need the best you can get.
For your mega slot consider pinsir honestly. I don't think scizor as the mega is worth it as it functions fine with out it. Mega pinsir is delicate but it really can sweep well.
Also see
>>32160454 pretty good suggestions. Mostly just play and see what fits your style, its hard to cover every need of bug with only six slots honestly. Bug is a hard type to run in all honesty.