Head Lice

Closeup photo of a single head louseThe Head Louse (Pediculus humanus capitis) is an insect pest which is an obligate parasite of humans, which means it is a type of parasite that cannot complete its life cycle without exploiting a suitable host.  It is gray in color but tends to take on the hair color of the host.  They are usually found on the lower back of the head and behind the ears.  The female is about 1/16″ to 1/8″ long and flattened in shape; the male is a bit smaller.  Head lice do not jump or fly.

A female head louse will live about 30 days on a host.  During this period, she will deposit about 90 eggs at a rate of three a day.  The eggs are called “nits” and hatch in about one week.  The life cycle is completed in about 15 days.  During this time, the nymphs, as well as the adults, feed with piercing and sucking mouthparts, injecting saliva to keep blood from clotting.  If the lice are not disturbed, feeding may continue for extended periods, and the insects may excrete dark red feces onto the scalp.

Additional Information: Head Lice