Fox Moth Caterpillars

Fox Moth Caterpillars

Observation - Fox Moth Caterpillars - UK and Ireland. Description: Found about 5 of these in total.I think these are all the same species, but of what I don't know Pictures 4 onwards show one on a leaf with some kind of egg sack of parasite attached to it? What could this be?

Found about 5 of these in total.I think these are all the same species, but of what I don't know

Pictures 4 onwards show one on a leaf with some kind of egg sack of parasite attached to it? What could this be?