Chrysalis of Swift Moth found protruding from ground

Today I found this empty "shell" (remains of the chrysalis) of a Swift Moth caterpillar's pupal stage, left empty when the adult moth emerged from the ground. I have seen such things before, (in other areas) left by Ghost Moths, which are even larger than this specimen.

This was the "rear end" of the Moth chrysalis.
This much was sticking out of the ground.

Scale shows it was slightly more than 70mm long.
The body end was quite firm still.
The "rear end" is fragile and weak.
The moth backs out of the case.

Given the number of Swift Moths I have seen recently I am going to assume that this belonged to Oxycanus dirempta.

The split in the shell is visible here.
That's where the Moth emerged.

"The Caterpillars of this species live in burrows they dig in the ground. Typically these are under Wattle bushes (Acacia species). They line their burrows with silk. They feed nocturnally, crawling out of their burrows to feed on leaves.

They pupate in their burrow. When the moth is ready to emerge, the pupa wriggles to the top of the burrow, and the empty skin is left poking half out of the burrow after the adult moth has departed."
Source: http://lepidoptera.butterflyhouse.com.au/hepi/dirempt.html

Here is one of these Head-banging Beasts.
At this time of year, they drive people mad in Robertson
desperately seeking lights, and sitting on windows.
The red eye is a reflection from the flash.
The other colours are normal.

Here is a slightly blurred image
But it shows the frantic wing beating
which makes them so noisy on our windows
It also shows the colour of the underside of all 4 wings.

Here are three different moths, showing the range of colours and patterns we get.
I have been advised (previously) that these are all representative of Oxycanus dirempta which is a "very variable species". So I was told.

My favourite pattern - with the strong white line

A fairly dull looking specimen
with a mix of checkerboard patterns, and
a broad light band across the foresings.
The hind wings are not visible when resting
in the "tent" position.

I really like the bright bronze colours
evident in many specimens like this one.