The photo shows parasites of some sort emerging from a final instar Northern Egger. This is a larvea I found on Norland Moor a couple of years back and reared through to final instar. I had a few larvea of Northern Egger and they did the usual cat thing of getting restless and roaming around the container looking for pupation sites when they finished feeding. I popped them in seperate containers and spotted this one would still not spin up when suddenly these white grubs started eating their way of the poor cat. When ever I see this photo it reminds me on John Hurt in Aliens ! Notice how the emerging larvae seem to be appearing just above the spiracular line on the cat.