Unless you pick it at the start of the game or trade it from someone else, starter Pokémon can't be found legitimately in Ruby. However, there are plenty of hacks and cheating devices that let you...
Put the Ruby game into the DS game-boy cartridge and then in the pearl starting screen you'll see a thing called transfer Ruby Pokemon. Then go to pal park. You need to see every Sinnoh Pokemon, and...
All Pokemon from Kanto, Johto, and Hoenn can be obtained in Ruby. Lotad, Lombre, Ludicolo, Sableye, Seviper, Lunatone, and Kyogre must be traded from Sapphire. Other Pokemon like the starters must...
to get heracross, you have to go to the safari zone. i suggest you go in with a lot of berries, because if you get close to him many times it runs away. so you have to throw him berries