44 ENTOMOLOGY 



aborted and the maxillae slightly developed, but with long 

 palpi, while the hypopharynx coalesces with the labium, and 

 there is no oesophageal bulb. 



Hymenoptera. In the honey bee, which will serve as a 

 type, the labrum (Fig. 54) is simple; the mandibles are well 

 developed instruments for cutting and other purposes and the 



FIG. 54- 



mjc 



Mouth parts of the honey bee, Apis mellifera. a, base of antenna; br, brain; c, 

 clypeus; h, hypopharynx; I, labrum; Ip, labial palpus; m, mentum; mo, mouth; mx, 

 maxilla; sm, submentum. After CHESHIRE. 



remaining mouth parts form a highly complex suctorial appa- 

 ratus, as follows. The tongue is a long flexible organ, ter- 

 minating in a " spoon " (Fig. 127) and clothed with hairs of 

 various kinds, for gathering nectar or for sensory or mechan- 

 ical purposes. The maxillae and labial palpi form a tube em- 

 bracing the tongue, while the epipharynx fits into the space 

 between the bases of the maxillae to complete this tube. 

 Through this canal nectar is driven, by the expansion and con- 

 traction of the tube itself, according to Cheshire, except that 

 when only a small quantity of nectar is taken, this passes from 

 the spoon into a fine " central duct," or also into the " side 

 ducts/' which are specially fitted to convey quantities of fluid 

 too small for the main tube. For a detailed account of the 

 highly complex and exquisitely adapted mouth parts of the 

 honey bee, the reader is referred to Cheshire's admirable work 

 or to Packard's Text-Book. 



Segmentation of the Head. The determination of the 



