This guide is a comprehensive listing of the locations of all 30 Fleas to be tracked down in Hollow Knight: Silksong. Blasted StepsThis Lost Flea is at the apex of the top-most silo in Blasted Steps, in a tiny niche. In this shaft, head up and right to the very end of this room to find the caged Lost Flea. Putrified DuctsA named Lost Flea called Vog is located at the very top of Putrified Ducts. The Lost Flea is trapped in a small niche at the very end of this gauntlet.