The mother, larger than the male, and equipped with a longer drill, is inspecting her acorn, doubtless with a view to depositing her eggs.
She goes over it step by step, from the point to the stem, both above and below.

On the warty cup progression is easy; over the rest of the surface it would be impossible, were not the soles of her feet shod with adhesive pads, which enable her to retain her hold in any position.
Without the least uncertainty of footing, the insect walks with equal facility over the top or bottom or up the sides of the slippery fruit.
The choice is made; the acorn is recognised as being of good quality.
The time has come to sink the hole.

On account of its excessive length it is not easy to manoeuvre the beak.

To obtain the best mechanical effect the instrument must be applied perpendicularly to the convex surface of the acorn, and the embarrassing implement which is carried in front of the insect when the latter is not at work must now be held in such a position as to be beneath the worker.
To obtain this result the insect rears herself upon her hind legs, supporting herself upon the tripod formed by the end of the wing-covers and the posterior tarsi.

It would be hard to imagine anything more curious than this little carpenter, as she stands upright and brings her nasal bradawl down towards her body.
Now the drill is held plumb against the surface, and the boring commences.