II FOOD OF INSECTS 63 



that each maxilla is hollow in its interior, for when 

 the tube is cut across it is best to cut it towards the 

 basal end it appears to be made up of three small 

 tubes, two lateral ones encompassing a central tube 

 between them. The inner or concave surface of the 

 maxillae which forms the tube is lined with a very 

 smooth membrane. In some species the extremity 

 of each maxilla is furnished along its anterior and 

 lateral margin with a great number of minute papillae 

 arranged in two rows ; to judge from their structure 

 and other circumstances, they may probably be 

 regarded as organs of taste. Among other curious 

 things the tube possesses some stiff, sharp-pointed 

 appendages along the inner anterior margin of each 

 maxilla, in the shape of hooks of marvellously small 

 size. When the proboscis* is extended they are be- 

 lieved to inosculate with each other, the hooks of the 

 one side with those of the other, just like the 

 dove-tailing of joiner's work, and to serve to unite 

 together the two halves, so that they form the anterior 

 surface of the canal. 



With this exquisitely simple mechanism butterflies 

 are able to probe to the bottom of the most variously 

 formed flowers, and to drain their honey. Not even 

 the nectar of the long narrow bells of the Marvel of 

 Peru or of the trumpet-shaped honeysuckle is safe 

 from their pliant trunks, hidden treasure that they 

 could never have had the opportunity of tasting had 

 they retained the short and more primitive biting 

 jaws. In the state of rest the tube is spirally coiled 

 up like the mainspring of a watch in front of 

 the head in small and convenient compass, and lies 



