PETER MATULAVICH / SCIENCE PHOTO LIBRARY PETER MATULAVICH / SCIENCE PHOTO LIBRARY
Head louse (Pediculus humanus capitis), about 3 mm in length, positioned next to U.S. 25-cent piece to show its relative size. Blood can be seen in its digestive tract. Lice are wingless, parasitic insects that spend their entire lives on the scalps of their human hosts. Their mouthparts, which are only visible when feeding, are adapted for piercing skin and sucking blood. The claws on their feet are used for grasping strands of hair.
Model release not required. Property release not required.