Pokedex

12 Butterfree

type bug/flying

Evolution 

Yellow         Red/Blue            Attack                   Type
*                     *                      Tackle                   Nrm
*                     *                       String Shot             Bug
*                      *                     Harden                  Nrm
10                   12                    Confusion              Psy
13                   15                    Poison Powder      Psn
14                    16                   Stun Spore            Grs
15                    17                   Sleep Powder       Grs
18                    21                   Supersonic            Nrm
23                    26                   Whirlwind             Nrm
28                                           Gust                      Nrm
34                    32                   Psybeam               Psy

* If evolved from a wild Metapod, it won't learn Tackle or String Shot and will learn Harden.

Tm 2, 4, 6, 9, 10, 15, 20, 21, 22, 29, 30, 31, 32, 33, 34, 39, 44, 46, 50

Not found wild in the game must evolve from metapod.