Avoiding darkness, they only emerged amid brightness, real or artificial. They congregated outside of every Reno, Nevada gambling club at the beginning of June, pestering the guests as they entered and exited. One night they even went so far as to invade the Palace Club casino. They, Feltia annexa (Treitschske), or Feltia subterranea, or the granulated cutworm, infested the city by the millions!
Due to a short lifespan, they were expected to die (by natural causes, that is) within a week’s time.
Photo from Wikimedia Commons: Adult Feltia annexa by Donald Hobern