4. BUGS 
The mouth-parts (Fig. 3) of all bugs are formed for piercing 
and sucking. They appear as a slender jointed beak, starting at 
the base of a shorter pointed upper lip or labrum. But this 
beak or rostrwi, usually composed of four joints, never more, 
is simply a horny, jointed, and tapering sheath, enclosing the true 
and real mouth-parts. If we dissect the beak, or rather remove 
Fic. 3.—Mouth-parts; a, of Reduvius, from side, after Smith; b, of Notonecta, 
after Miall; c, of Bed-bug, original; d, of Aphis, after Smith. 
it entirely, we can detect four bristles, two of which represent 
the mandibles, and two the maxille. Maxillary palpi are want- 
ing. The four bristles are adapted for piercing the tissues of 
plants, or the skin of animals. Sometimes the beak is very long 
and slender, or it is short and thick. The length of the beak 
depends upon the food-habits of the bug, whether it has to probe 
deep into the plants, or finds liquid food near the surface. 
