The cup moth (family Limacodidae) is so-named because its cocoons resemble cups, as shown by the set I found on the Illawarra flame tree (Brachychiton acerifolius) up the back of the property.
Cup moth cocoons; photo by Andrew Roberts
The caterpillars have already left these cocoons.
Relative size of cup moth cocoons; photo by Andrew Roberts
Cup moth caterpillars are spectacularly coloured, with don’t-mess-with-me irritating hairs that stand up in groups on the body. The hairs lodge in the skin and cause wheals and rashes.
These caterpillars are sometimes called Chinese junks, presumably because of the shape of the body, but they have other common names (some unprintable, as anyone affected by these can attest).
A-roving I will go 
Well, yes I can vouch for the pain inflicted by those pretty caterpillars.
Unguarded skin on underarm, when clearing up a fallen Cootamundra Wattle.
Stung for about 36 hours.
I always wear long sleeves these days.
Denis