The Cocoon 



this possibility : it glues a few grains together 

 and makes a rough curtain of sand, which 

 stops up the orifice very imperfectly, but 

 sufficiently to prevent an accident. Having 

 taken these precautions, the larva works at 

 the back half of the cocoon. From time to 

 time, it turns round to fetch fresh supplies 

 from outside, tearing a corner of the cur- 

 tain that protects it against the outer sand 

 and grabbing through this window the ma- 

 terials which it requires. 



The cocoon is still incomplete, wide open 

 at the big end; It wants the spherical cap 

 that is to close it. For this final labour the 

 grub takes a plentiful supply of sand, the 

 last supply of all, and then pushes away the 

 heap outside the entrance. At the opening 

 it now weaves a silken cap, which fits the 

 mouth of the primitive eel-trap precisely. 

 Lastly, grains of sand, kept in reserve in- 

 side, are laid one by one upon this silken 

 foundation and glued together with silky 

 slime. Having finished this lid, the larva 

 has nothing else to do but give the last finish 

 to the inside of the abode and glaze the 

 walls with varnish to protect its delicate skin 

 against the rough sand. 



The hammock of pure silk and the hemi- 

 327 



