Trapinch-Vibrava-Flygon has never made the most sense to me. Trapinch has a massive head with a big mouth, then evolves into a pretty dragonfly-like animal with a much smaller head and mouth, before then evolving into a large bug-dragon.
Trapinch is supposed to be an Antlion, the lava form of the lacewing which Vibrava resembles. As for Vibrava to Flygon, pass. Think I would have liked it to remain as a part bug type but that could be just me.
I guess through evolution Pokemon change in many ways, including appearance. No one said they had to make sense, haha!