Richard S. Miller, writing in American Beetles (2002), comments that many while authorities state that Net-winged Beetle larvae are predators, such statements are based on anecdotal evidence. Miller argues instead that "most, if not all" Lycid larvae feed on slime molds or on the "metabolic products of fungi."
Miller gives these common locations for Lycid larvae: in rotting logs, in leaf litter, under the bark of dead trees, and, in the case of genus Lycus, "moving over open ground in the early evening." The Lycus shown here was getting an early start; it was photographed moving across a large rock in West Virginia at 1:47 p.m. The date was somewhat early for beetle larvae to be out in the open, too: April 29.
American Insects site