The entomological literature,1977,states that the Figwort beetle,Cionus scrophulariae's larva spins it's cocoon taking fine threads of silk from it's anal segment with it's mouth!
It does no such thing!
It's initial cocoon skin forms on the body of the larva - then it curls into a ring & re-inforces this from the inside with milky globular lumps taken from the anus with it's mouth & bunged into place.
They've known about Cionus cocoons for 150 years.
At present it seems as if i'm the only one to have viewed Cionus cocooning under a microscope!Only 10 & 20 times magnification needed.
14/9/10; A 1902 article describes the cocooning very well but omits the hole in the centre that it struggles to fill in,so I could submit a note on that; Cionus weevil has a long 'snout' with teeth @ the end,is 5m.m.long,with 'furry'patterns on it's 'wings';It's unnusual for beetles to make cocoons.