12 LICE AND THEIR MENACE TO MAN 



splits and allows the louse to creep out. It is 

 naturally very soft when it first emerges from 

 its old skin, and is white and semi-transparent. 

 It soon hardens and takes on in parts a sepia 

 tint, which varies much in density, being darker 

 on the lice which infest dark-skinned races. 

 Often it appears to have a sepia-coloured border 

 running all around the edge of its body. 



In the following description of the adult louse 

 reference should be made to Fig. 1 and to Fig. 3. 

 The latter is a diagram representing some of 

 the more important organs of a female louse 

 which would be s'een if the insect were cut clean 

 down the middle line and one half removed. 

 Where an organ is paired, only those of the right 

 side of the body are thus represented. 



The body is divided into three regions, the 

 head, the thorax, and the abdomen. The head 

 is attached to the thorax by a very narrow neck 

 and has a considerable power of independent 

 movement, up and down and from side to side. 

 Between the thorax and abdomen, at the waist, 

 there is hardly any constriction at all. The 

 head is rather pointed in front and rounded 

 behind. It bears at the tip, and just below it, 

 a circular opening, the mouth, which is surrounded 

 by a ring of pliable tissue, the haustellum, which 

 bears a number of hooks (Fig. 3, 1). At the 

 sides of the head are attached the antennae 

 or feelers, which are composed of five joints. 

 The antennae bear hairs which have a sensory 



