INSECTS : THEIR MOUTHS. 177 



circle, but only about two-thirds of a circle, leaving a 

 blank space ; and the tips of the wires end alternately 

 in a fine acute point, and in a rounded fork, like the 

 prongs of a pitch-fork. It has been said that these 

 tubes are modified trachece ; but this fact is by no 

 means obvious to me ; for so far from their being con- 

 nected with the general tracheal system, each of the 

 four main tubes originates in an open centre, and each 

 with an open extremity. I think it likely that they are 

 so many suctorial pipes, thi-ough which the fluid to be 

 drunk is pumped up, entering at their minute open 

 tips, and discharging itself into the central cavity, by 

 the open basal extremities of the main tubes. 



The most extraordinary modification of jaws, how- 

 ever, is the long spii-al tube which is ordinarily coiled 

 up under the face of a Butterfly or Moth, with which 

 it pumps up the sweet nectar of flowers. Many flow- 

 ers have a deep corolla, and most have the bases of 

 their petals, where the nectar lies, so far from the level 

 of the surface, that probing is necessary to reach it. 

 Bees can enter tubular flowers, and lick their bottoms ; 

 and even blossoms that are closed, as the Snapdragon, 

 they know how to force and enter. But Butterflies, 

 with their wide wings, incapable of being folded, can- 

 not enter flowers bodily, and therefore a peculiar ap- 

 paratus is given them for robbing their contents, as it 

 were, at the doors. 



Nothing is easier than to examine this beautiful or- 

 gan with the naked eye ; and much may be learned of 

 its structure by means of a pocket lens. You may thus 

 see in a moment, that it forms a flat spiral of several 

 coils, like the mainspring of a watch ; that it runs off 

 to a point, and that this point is double, for it is fre- 



