Rapier Wasp

Presumed to be a small wasp like creature with 'Rapier' like tails.

RWBY
They make a first appearence in Episode 13 when Jaune is asked to collect some for Cardin but are only shown as a buzzing cardboard box with a 'W' on the front.

Trivia

 * These are (most likely) the first comfirmed creatures to exist in RWBY that are not Human or Grimm, excluding the signature Crow in the Trailers