INSECTS 125 



viewed from the front. When open, the mandibles project ven- 

 trally and disclose the underlying structures. 



(/) Projecting below the mandibles and attached to the ventral 

 surface of the head is the prominent feeding organ, or proboscis, 

 composed of several separate structures, namely : (a) a long, 

 median, flexible tongue (glossa) with a spoon-like tip (label- 

 lum) ; (b) a pair of jointed labial palps which lie next to the 

 tongue ; and (c) a pair of maxillae situated lateral to the labial 

 palps. 



The mouth parts of the worker are used in many ways, and their 

 structure is such that they are adapted for sucking nectar from 

 flowers and for chewing solid materials, such as pollen grains and 

 wax. The Bee, in collecting nectar from flowers, brings together 

 the maxillae and the labial palps, lying on either side of the tongue, 

 to form a tube which encloses the tongue, and in which the latter 

 can be moved back and forth. The drops of nectar are first col- 

 lected on the hairs which cover the tongue. Then they are forced 

 upward by the movements of the tongue and by suction from the 

 pharynx. 



2. Thorax 



The thorax consists of three segments, each of which bears a 

 pair of legs. These are known, beginning anteriorly, as the 

 prothoracic, mesothoracic, and metathoracic segments. The 

 paired legs are named in accordance with the segment to which 

 they are attached. The mesothoracic and the metathoracic seg- 

 ments each bears a pair of wings in addition to the pair of legs. 

 The wings consist of a thin, secreted, chitinous material supported 

 by tubular, vein-like structures. The two wings on the same side 

 of the body may be fastened together by means of a row of hooks 

 which are present on the anterior margin of the hind wing, and 

 which can be inserted in a receptacle on the posterior margin of the 

 anterior wing. When the Bee is flying, the wings are widely 

 extended. When at rest, the wings are drawn close to the body 

 on each side. Both the wings and the legs are operated by very 

 powerful muscles which lie in the thoracic cavity. (W. f. 216.) 



Structure and Functions of the Legs. The three pairs of 

 legs of the Bee are beautifully adapted for the various necessary 

 types of work. They are, indeed, to be ranked among the most 

 remarkable structures that are found in the Insects, or for that 

 matter in any other group of animals. The fundamental structure 



