Harvey. Have you another image? What's that dark shape at the bottom end of the caterpillar? It looks too sharp to be shadow.given we apparently have a very hairy species.
Hi Ian - no, this is the only image I have. I didn't use flash, but I do think the shadow below the head is just that; the shadows of individual hairs are also clearly visible. I reckon about half of the dark blob is head capsule in shadow (due to angle of the light) and the rest is shadow on the tree trunk from the head capsule.