Extension > Garden > Diagnose a problem > What insect is this? > Insects found indoors > Beetles, bugs, ants, and other insects without obvious wings - Under 1/4 inch long > Book louse
Jeff Hahn, University of Minnesota Extension
Ken Gray Collection, Oregon State University
Description: Up to 3/16 inch long
Where/When: Found outdoors, on tree bark, plant foliage, or under stones. Found indoors in damp, warm, undisturbed places where mold and fungi are growing, especially during spring and summer.
Significance: Nuisance. They are harmless to people and essentially harmless to property; on rare occasion, they can damage some paper products.