NUTRITION PROPER. 



335 



Bees are a good example of intermediate form (Fig. 

 217). In these the labrum and mandibles are as usual, 

 but the maxillag and labium, with their appendages, are 



Fig. 217. — Head of a bee seen from Fig. 218. — A, enlarged view of a bee's 



behind. The labrum is not seen. tongue ; r, inner tube ; B, section 



The other parts are lettered as be- more enlarged, showing its struc- 



fore ; t, tongue. ture. 



greatly elongated to form a sucking organ. This is 

 especially true of that projection of the labium called 

 the tongue, /, which is modified into an apparatus of 

 marvelously complex structure. This is shown in Fig. 

 218, in which A shows the outer tube with the inner tube 

 23 



