Bag-shelter Moth - Ochrogaster lunifer
On the mainland, Ochrogaster lunifer is just about Australia wide and because of this wide distribution can be highly variable in color and markings. Amongst moth entomologists there is the suspicion that there may be more than one species represented under the O. lunifer banner. The one photographed above is one of the more unusual and highly spectacular forms, plus the abdomen is horizontally striped with bright orange and black bands, so quite a stunning individual.
The males are around 2.5 cm (1") long and are seen during October and November and unerringly follow the pheromones of the female moths in the sandy heaths around Esperance. They are however only around for a short period, as they have no mouth parts to feed and so die within a few days after they have mated and hopefully started a new generation.
The caterpillars are known as Processionary Caterpillars and move head to tail in line from one food source to another. As a word of warning, the hairs on the caterpillar, their silken nests and those on the tail end of the adults can cause skin rashes, so should be avoided, but they are nevertheless well worth a prolonged gander.
August 2013 update
Two photos added and two old ones removed.