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[Pediculus humanus capitis] [Pediculus humanus humanus]

Body and head lice (Pediculus humanus humanus and P. h. capitis, respectively) cause a condition in humans known as Pediculosis.  Although body lice are usually found on the torso, and head lice are found on the head and face,  both species may change location.  Adult females are approximately 3-4 mm long; males are slightly smaller.  Pediculus can be distinguished from the pubic lice (Phthirus pubis) by a larger length:width ratio of the body.  The legs are adapted for clinging to the host's hair.  Eggs (nits) are laid on hair shafts and are held tightly by a cementlike substance, making them difficult to remove.

A	B

A: Adult of P. humanus capitis.
B: Adult female of P. humanus capitis.  In this specimen, eggs can be observed in the abdomen.

 

C

C: Adult of P. humanus.