From Halopedia, the Halo wiki
Yanme'e Ultras are distinguished by their blue and cyan exoskeletons, along with paired forked horn-like structures on their head and cephalothorax. Yanme'e Ultras are often armed with Type-25 plasma pistols, and sometimes Type-33 Needlers. Ultras are equipped with anti-gravity technology that is attached to their wings that allow them to fly freely. Some Yanme'e may instead be distinguished by the presence of a silver-white exoskeleton and a yellow-hued set of antigravity emitters..
Halo 3: ODST
These Drones are tougher than the Minors or Majors. Unlike most lower-ranking Drones, Yanme'e Ultras often land on the ground when engaged in combat, making them an easier target. In Halo: Reach, using the Thunderstorm skull causes all Drones to either spawn as the Major or Ultra rank. Automatic weapons are useful at killing the Drone.
List of appearances