THE HEAD-LOUSE 71 



are most careless in the care of the person. 

 Females are more often infested than males, as 

 the hair is longer, affording better concealment 

 for the lice. While the insects may be found all 

 over the head, the parts most frequented are the 

 sides, over the ears, and back, rather than on the 

 crown. The eggs are laid attached to the hair 

 close to the scalp, but as the hair on which they 

 are situated grows they become more distant 

 from it, and hatched nits may be found quite 

 a long way from the base of the hairs. It is 

 possible that the eggs may occasionally be laid 

 in hats, attached to the cloth of the lining. In 

 correlation with the smaller size of the parent the 

 eggs of the head-louse are somewhat less than 

 those of the body-louse, and the fecundity is 

 not so great. Otherwise there is little difference 

 between the two races in their life-history and 

 their responses to environment. 



The spread of head-lice is by methods similar 

 to those which obtain in body-lice. A person 

 may become infested by stray lice ; by coming 

 in contact with a lousy person ; by using the 

 brushes or head-gear used by one who harbours 

 the lice ; by having had his hat in contact with 

 one containing lice. The cloak-room system of 

 our council schools, where hats are hung on pegs 

 in close proximity, and often several on one peg, 

 lends itself to the dissemination of this insect. 



The presence of the first intruder is more 

 likelv to be noticed than in the case of the body- 



