192 



THE EVOLUTION THEORY 



.G.U. 



is only partial, the lobes having remained separate (le and li) ; and the 

 same is true of the bee, but in this case the inner lobes have grown 

 into a long worm-like process which is thrust into the nectar in the 

 act of sucking. 



Even the_ burrowing- wasps exhibit the beginnings of variation in 

 this direction, for the under lip is somewhat lengthened and modified 

 into a licking organ. The adaptation has not gone much further than 



this, even in one of the true 

 flower-bees, Prosopis, which feeds 

 its larvae with pollen and honey, 

 and it is only in the true honey- 

 bee that the adaptation is com- 

 plete (Fig. 49). Here the so-called 

 'inner lobe' of the under lip (/£)has 

 elongated into the worm-shaped 

 process already mentioned ; it 

 is thickly covered with short 

 bristles, and is called the ' tongue ' 

 of the bee (li). The outer lobes 

 of the under lip have degenerated 

 into little leaf-like organs, the 

 so-called accessory tongue or 

 paraglossa (le), while the palps 

 of the under lip (pi) have elon- 

 gated to correspond with the 

 tongue, and serve as a sensitive 

 and probably also as a smelling 

 organ, in contrast to the palps 

 Fig. 49. Head of the Bee. ^compound f the first maxillae, which have 



eyes, au, ocelli, at antenna?, la, upper lip. 



md, mandibles. mx\ first maxilla?, with pm, shrunk to minute stumps (pill). 



the rudimentarymaxillarypalp. wx* second Th h d f th d i- h ; h 



maxilla? with the internal looes (h) iused to r ' 



form the 'tongue.' le, the external lobes of has elongated even ill its basal 



the second maxilla?, known as ' paraarlossa?.' ,• ? -m ,1 n 



pi, labial palp. portions, forms, with the equally 



long first maxillae, the proboscis of 



the bee. The first maxillae are sheath-like half -tubes, closely apposed 



around the tongue, and form along with it the suctorial tube, through 



which the nectar is sucked up. Thus, of the three pairs of jaws 



in insects, only the first pair, the mandibles, have remained unaltered, 



obviously because the bee requires a biting-organ for eating pollen, 



for kneading wax, and for building cells. 



But bees do not only feast on nectar and pollen themselves, 



they carry these home as food for their larvae. The form already 



