SUCKING-LICE. 95 
ter were such a common occurence that few school rooms 
could boast of not having such inhabitants. It shows that 
civilization after all depends largely upon the free use of soap 
and some mechanical appliances as fine-toothed combs. 
Lice are true insects furnished with a sucking mouth 
(fig. 65). They are very degraded insects, however, and do 
not even possess wings, for which they have no use, being 
generally surrounded in their dwelling-places by plenty of 

Fig. 65.—Mouth-parts of body-louse; a, a, summit of head with 
bristles; b, b, the chitonous band; c, hind part of lower lip; d, d. 
protruding part of lower lip (haustellum); e, e, hooks turned out- 
wards; f, inner tube of suction, with two pairs of jaws shown as 
lines on the outside, and a few drops of blood in the interior. 
Greatly enlarged. After Schicedte. 
food. The small head is conical; the thorax is also small 
and indistinctly segmented; the abdomen, however, is large, 
flat, round or oval, and contains nine segments. The slen- 
der feelers possess five joints; the simple eyes, if they possess 
any, are minute; the feet have two joints, of which the last 
one forms a strong hook for grasping the hairs while climb- 
ing upon them. The mouth forms a very slender, fleshy 
