Habitat
For shelter the louse depends upon the clothing, particularly the garments worn next to the body, and prefers the comfort of the seams. Soldiers express a habit of the insect graphically when they say "it digs itself in", and for this purpose the beautiful musculature and the strong claws and spines of the legs are admirably adapted. The shirt is preferred, but in many cases most eggs are found at the fork of the trousers. This is because the trousers are worn consecutively for a much longer period than the shirt. In order of importance the areas most favoured for egg laying are the fork of the trousers and the armpits and the triangles at the tail of the shirt. Next are the trousers and the shirt seams and the neck, but under present conditions there is general distribution also. Eggs have even been found in the beads of rosaries. It will be noticed that the insect accumulates where there is plenty of warmth, plenty of humidity and plenty of shelter.

The possibilities of infestation are instanced in a case examined at a hospital. Apart from extreme lousiness of under clothing, the man actually had lice and eggs at the back of the neck of the tunic, the pocket seams inside the tunic and the flap seams of the pockets. A walking distributing agent!

The process seems to be: The stabbing organs are out-thrust, pierce deeply and the sucking tube is anchored by the circum-oral teeth to the skin; by means of muscular action on each pharynx the blood is drawn in; leakage into the sac of the stabbing organs is prevented by the upper stabber; the salivapours into the sac, and possibly via a tube formed by the upper and lower stabbers reaches the wound and prevents the coagulation of blood; the blood is digested in the stomach and intestine; the waste products from the gut and Malpighian tubules pass through the rectum and anus.