THE CAPEICORN 145 



brought up the same distance. With this object the front 

 pads fill out and provide support, while those behind shrink 

 and leave room for the grub to draw up its hind- quarters. 



With the double support of its back and stomach, with 

 alternate swellings and shrinkings, the animal easily advances 

 or retreats along its gallery, a sort of mould which the contents 

 fill without a gap. But if the pads grip only on one side 

 progress becomes impossible. When placed on the smooth 

 wood of my table the animal wriggles slowly ; it lengthens 

 and shortens without progressing by a hair's-breadth. Laid 

 on the surface of a piece of split oak, a rough, uneven surface 

 due to the gash made by the wedge, it twists and writhes, 

 moves the front part of its body very slowly from left to right 

 and right to left, lifts it a little, lowers it, and begins again. 

 This is all it can do. The rudimentary legs remain inert and 

 absolutely useless. 



II 



THE GRUB'S SENSATIONS 



Though the Capricorn-grub possesses these useless legs, 

 the germs of the future limbs, there is no sign of the eyes with 

 which the fully-developed insect will be richly gifted. The 

 larva has not the least trace of any organs of sight. What 

 would it do with sight, in the murky thickness of a tree- 

 trunk ? Hearing is likewise absent. In the untroubled silence 

 of the oak's inmost heart the sense of hearing would be super- 

 fluous. Where sounds are lacking, of what use is the faculty 

 of discerning them ? 



To make the matter certain I carried out some experi- 

 ments. If split lengthwise the grub's abode becomes a half- 

 tunnel, in which I can watch the occupant's doings. When 

 left alone it alternately works for a while, gnawing at its 

 gallery, and rests for a while, fixed by its pads to the two 

 sides of the tunnel. I took advantage of these moments of 

 rest to inquire into its power of hearing. The banging of hard 



