Things You'll Need
Instructions
Capture three Burmy Pokémon: one male, one female and one more of either gender. Burmy are Bug-type Pokémon, and you can find them in the wild hanging around Honey Trees. To attract one, find a Honey Tree and spread some honey on it. Leave the area and return in about nine hours to find a Pokémon. Unfortunately, it may or may not be a Burmy; if it isn't a Burmy, you'll have to keep repeating this step until one appears, which can make the task take awhile to complete.
Level up one male and one female Burmy until they reach Level 20; the third Burmy can be any level below 20. Do this either by using your Burmy in battle or by feeding them Rare Candy to speed up the process; one Rare Candy boosts a Pokémon's level by one. Once they reach Level 20, the male evolves into Mothim and the female evolves into Wormadam.
Travel to Pastoria City and go to the PokeMart. Travel just north of the store to find a boy in a hat. Place Burmy, Mothim and Wormadam in your party and speak with the boy to show them to him. In exchange, he gives you the Macho Brace.