From Halopedia, the Halo wiki
Pupal-stage Yanme'e are only found inside Yanme'e hives, in which they grow. Their bodies emit a yellow glow, which is not present in later stages of Yanme'e life cycles. Even when dead, their bodies and carapce continue to emit a glow. They are extremely weak and susceptible to gunfire, moreso than most Yanme'e, and only equip Type-25 plasma pistols.
Halo 3: ODST
Pupal Yanme'e only appear in Halo 3: ODST. They can be easily identified in dark levels such as Crater (Night) and Data Hive thanks to their glowing bodies. They are susceptible to gunfire and will die in only one hit from any weapon.
In the campaign, pupal Yanme'e can only be found in the hive section of the Data Hive level; in this section, swarms of such enemies will continuously harass the player and Dare, though their easy dispatch makes them easy to take down. They are the only Yanme'e type to spawn in this section, with the exception of the Yanme'e Captain Major near to the end.
List of appearances