each side a long appendage; these are the labial palpi (Plate XXV, 3, p).
The thorax.—The thorax is the central region of the body. It consists of three body-segments, which are grown together so compactly in the adult insect that it is difficult to distinguish them. The thorax bears the organs of locomotion, the wings and the legs.
There are two pairs of wings; but the two wings of each side are so closely united that they appear as one. The union is accomplished by a row of hooks on the front edge of the hind wing, which fasten into a fold in the hind edge of the fore wing. The wings are strengthened by a framework of heavy lines, which extend in various but definite directions. Between these lines the wing is a thin membrane.
There are three pairs of legs, a pair borne by each of the three body-segments of which the thorax is composed.
Each leg consists of nine segments and a pair of claws at the tip of the last segment. The first two segments, the coxa and the trochanter, are short; then follow the two principal segments, the femur, or thigh, and the tibia, or shank; the five remaining segments constitute the tarsus or foot. A striking peculiarity in the tarsi of bees is that the first segment differs greatly in form from the other segments and is much larger, approaching the tibia in size. This enlarged tarsal segment has received the special name of metatarsus.
The legs serve several functions besides that of
