You need to surf to Route 18 first. Then, find a house near a bridge. There will be 2 or 3 people inside. One of them will give you a Larvesta egg, which will hatch into a level 1 Larvesta.
Larvesta evolves at level 59 in both Pokemon Black and Pokemon White.
You get it in an egg on route 17 or 18
route 17 talk to the PKMN ranger in the little house
Larvesta evolves into Volcanra once it reaches level 59
Volcarona (Bug/Fire)
It evolves at Lv59.
Larvesta
You can't, It is only obtainable in Pokemon Black or White. But if you want one in Black or White, a Pokemon ranger will give you an egg of a Larvesta in Route 18 so remember to make room for it!
level 59
Larvesta is a Bug and Fire type pokemon.
At level 59, it will evolve into Volcarona.
you will get larvesta, a bug/fire type pokemon.