Abstract: The nit of the head louse(Pediculus humanus capitis) was studied with.SEM.The results were as follows:The lower part of tfie egg shell was attached tightly to the side of the hair,The unhatched nit had an opercylum on its tep.The protruded egg lid on the operculum consisted of nine equal-sized small oral chambers arranged in three lines,There was a pore in its center about l0 mu is diameter.Neither inter chamber reticular cement nor special stripe on the egg shell was found.After hatchin8 the operculum dropped off,and the egg shell sankin the empty nit.