Speak with Pixni Rustbomb.
The dark blade of Sargeras has cast a shadow of destruction over this land. It seemed that the silithid hives were destroyed in the attack, but I have received reports that the silithid are returning. If it were up to me, I'd burn those wretched hives once and for all! However, it is not up to me. The Dark Lady wants the surviving silithid dissected and studied. Pixni Rustbomb is conducting the research and is in need of a "collector."