Insects Very few different kinds of insects are parasitic on humans, and most of these are biting flies. All of these insects feed on blood. However, only two kinds will remain on the skin or in clothing for any length of time. These are the lice and fleas. Lice are host specific parasitic insects.
All life stages feed on blood.
The different developmental stages, including the eggs, are easy to see. Lice cause intense itching in affected areas and pink papules. To order an info sheet on lice, go to the Bohart Museum info page . Fleas only feed on humans and other mammals in the adult stage. The larvae are scavengers in animal nests or carpets.