HOW ANIMALS EAT. 



59 



the Bee tribe, we have a transi- 

 tion between the biting and the 

 sucking Insects the mandibles 

 "supply the place of trowels, 

 spades, pickaxes, saws, scissors, 

 and knives," while the maxillae 

 are developed into a sheath to 

 enclose the long, slender, hairy 

 tongue which laps up the sweets 

 of flowers. In the suctorial But- 

 terfly, the lips, mandibles, and 

 palpi are reduced to rudiments, 

 while the maxillae are the only 

 useful oral organs. These are 

 excessively lengthened into a 



proboscis, their edges locking 



by means Of minute teeth, SO as 

 f i i ,1 i 



tO form a central Cacal, through 



which the liquid food is pumped 

 up into the mouth. Seen un- 

 der the microscope, the proboscis 

 able rings interlaced with spiral 



HJ. 22. Head of a Wild Bee (An- 

 thophora retusa), front view: o, 

 compound eyes; 6, clypens; c, 

 three simple eyes; d, antennae; e, 

 l ab rnm : /, mandibles; 



is made up of innumer- 

 muscular fibres. The 

 proboscis of the Fly 

 is a modified lower 

 lip ; that of the Bugs 

 and Mosquitos, fitted 

 both for piercing and 

 suction, is formed by 

 the union of four 

 bristles, which are 

 the mandibles and 

 maxillae strangely al- 

 tered, and encased in 

 the labinm when not 



FIG. '23. Prubu:-cis of a Butterfly, magnified. in US6. 



