are doubtless sense organs; and it is believed that certain microscopic pits, which occur in great numbers in their cuticle, are the organs of smell. It is possible, also, that the antennæ function as organs of touch, certain hairs with which they are furnished being the tactile organs.
The mouth-parts are very complicated. They consist of an upper lip, a lower lip, and two pairs of jaws between the lips.
The upper lip is known at the labrum. It is a flap-like projection situated above, or in front of, the other mouth-parts (Plate XXV, u).
The first pair of jaws, those situated nearest the labrum, are the mandibles (Plate XXV, 3, md). Each mandible consists of a single hard piece. They are the biting organs. Certain wild bees, distantly related to the honey-bee, dig holes in wood with their mandibles for nests for their brood. The honey-bee uses its mandibles as tools for the manipulation of wax and propolis, and as weapons in its combats.
The second pair of jaws, which are situated between the mandibles and the lower lip, are the maxillæ (Plate XXV, 3, mx). Each maxilla is a long blade. The maxillæ, combined with the lower lip, constitute what, in popular language, is known as the tongue, the organ by means of which the food is conveyed to the mouth, or the nectar extracted from a flower.
The lower lip, or labium (Plate XXV, 3, l), is the long central part of the so-called tongue; it bears on
