The shank forms a veritable saw, but with two parallel sets of teeth; and it is so strongly made that it may well be compared, the question of size apart, to the great saw of a quarry-man.
The shank of the larva has the same structure, so that the object to be extracted is enclosed in a scabbard as awkwardly shaped as itself.

Each spur is enclosed in a similar spur; each tooth engages in the hollow of a similar tooth, and the sheath is so closely moulded upon the shank that a no more intimate contact could be obtained by replacing the envelope by a layer of varnish applied with a brush.
Nevertheless the tibia, long and narrow as it is, issues from its sheath without catching or sticking anywhere.

If I had not repeatedly seen the operation I could not believe it possible; for the discarded sheath is absolutely intact from end to end.

Neither the terminal spurs nor the double rows of spines do the slightest damage to the delicate mould.

The long-toothed saw leaves the delicate sheath unbroken, although a puff of the breath is enough to tear it; the ferocious spurs slip out of it without leaving so much as a scratch.
I was far from expecting such a result.