LIFE-HISTORY OF THE BODY-LOUSE 27 



first time. From the time of hatching to its 

 becoming full-grown the louse under the most 

 favourable conditions occupies about eight or 

 nine days. Allowing a period of eight days in 

 the egg, we see that from the time that the egg is 

 laid to the time when the louse is ready to begin 

 breeding there is a period of about seventeen 

 days. This obtains only when the louse is in 

 continual contact with the body, and is prolonged 

 by adverse conditions, such as its cooling at night 

 owing to the putting off of garments. 



Feeding. Under normal conditions the louse 

 feeds about four to six times a day, preferring to 

 do so when its host is at rest, sitting or sleeping. 

 It does not leave the clothing and creep on to the 

 body to feed. All that is necessary is for it to 

 be able to touch the skin with its mouth. If lice 

 are put on to small fragments of cotton and these 

 on to the skin, they will be seen to feed in all 

 positions, some at right angles to the surface, 

 and some even with their backs to it, the head 

 being thrown backwards till the mouth touches 

 the skin, while the legs feebly grip the cotton or 

 even wave in the air. For this reason lice bite 

 mostly those parts of the body, such as the hips, 

 shoulders and neck, and fork of the legs, where 

 the garments press closely against the skin, and 

 avoid more the parts where the clothing is slack. 

 Soldiers who wear body-belts often find that they 

 are intensely irritated by bites in this locality. 

 This habit of not leaving the clothing to feed is 



