68 INSECT LIFE IN POND AND STREAM 



a looper catterpillar ; or, fixed to the under 

 surface of a leaf by a sucker on its tail, it 

 hangs head downwards, sweeping the particles 

 of food which float by in the swiftly moving 

 stream into its tiny mouth with its waving 

 hairs. 



If the little creature is startled it instantly 

 drops from its leaf, but it is not, as one might 

 suppose, swept away by the current. It has 

 let itself down by a silken rope, just as a cater- 

 pillar swings down from a tree, and as soon as 

 it has recovered from its alarm, it will proceed 

 to haul itself up again. It can spin threads 

 almost as well as a spider can, and makes a 

 perfect network round about, stretching from 

 leaf to leaf. Along these threads it travels at 

 lightning speed when it wishes to change its 

 position. 



Before changing to a pupa the larva does 

 not leave the water, but weaves a silken cocoon 

 which it fixes to the stem of a water weed like 

 a tiny pocket. At first the pocket is closed, 

 but as soon as the larva has cast its skin and 

 become a pupa it pushes it open at the top, 

 and a strange-looking head, still adorned with 

 tufts of hair, appears over the top. The pupa 

 holds fast to the inside of its pocket by a 



