Green Zebesians appear in Super Metroid and can be found in Crateria a few rooms before the entrance to the rebuilt Tourian and in Kraid's Lair where they, along with green Kihunters, serve as guards for Kraid. The first time they are encountered, Samus can only use Missiles and Bombs to destroy them. Once she acquires more powerful Beams or other weaponry, she can destroy them without using either Bombs or Missiles. According to the Super Metroid Nintendo Player's Guide, they have a 20% chance of leaving a small Energy Capsule after death, a 12% chance of leaving a large capsule, 39% Missile Ammo, 8% Super Missile Ammo and 4% Power Bomb Ammo.
Super Metroid Players' GuideEdit
"You'll encounter these quite a lot as they patrol horizontal platforms. They vary considerably in strength; the further you progress the tougher they are. Use missiles if possible to destroy them."