The Yam'rii, or Huk as they were commonly known, were a species of giant praying mantises. They were quite aggressive, which was why they attacked the Kaleesh. That turned out to be a big mistake, since Grievous got pissed and PWNed them (this was before Grievous was turned into a cyborg). They were getting PWNed so hard that the Galactic Republic and Trade Federation came in and saved their asses. After Grievous was turned into a robot, he took a droid army and PWNed the Yam'rii again, although they didn't go extinct just yet.
A long time later, some Yam'rii were mind-controlled by the buggers during their reign of terror, along with a bunch of other insect species.