226 HYMEXOPTERA. 



structures and modifications after they have been orig- 

 inated by the action of physical and other causes.^ 



The antennae (PL X., Fig. 177, at) are distinctly bent 

 or elbowed. The strong, horny mandibles (Fig. 177, 

 md) are used for biting, like the same organs in the 

 mandibulate insects, while the two pairs of maxillae 

 (see PL X,, Fig. 178) are for piercing, sucking, and 

 lapping. Fig. 178, ro, are chitinous rods connecting 

 the first pair of maxillae with the second ; lg\ the funnel 

 or sucking-disc of the ligula ; and pgl, two leaf-like 

 sections or secondary palpi known as the paraglossae. 

 The other parts are lettered as before. The ligula {Ig) 

 is the part which is popularly known as the proboscis, 

 trunk, or tongue, and is not solid, but a tube-like suck- 

 ing-organ for obtaining fluids.- The length of the pro- 

 boscis varies in difterent species, being adapted to the 

 varying length of the tubular corollas of flowers. The 

 mouth parts of the honey-bee offer one of the best 

 illustrations of the process of specialization by addi- 

 tion. This process has been carried so far that the 

 organs have become greatly differentiated from the 

 primitive type, complex in structure, and capable of 

 performing skilfully different kinds of work. 



The legs (PL X., Fig. 177, /', /", /'") are strong, 

 hairy organs adapted for walking. The last pair (/'") 

 in the worker are also used for storing pollen, the under 

 side of each tibia, which is protected by long, curving 

 hairs, being used for this purpose. The first section 

 of the foot is very large, and marked by lines of bril- 



1 See pp. 16, 40-42. 



^ For figures, see Amer. Quart. Micr. yoiirnal. Vol. I., No. 

 4, July, 1879. 



