Cuckoo wasps roll into a tight ball when disturbed or attacked. Many are parasitic on bee or wasp larvae, some attack Symphyta larvae and one attacks Phasmid eggs. Most occur in woodlands. I found this single specimen rummaging around in the holes of a dead tree where ichneumon wasps were having a field day, too. I'll apologize for the poor quality of these pictures - this wasp was very shy and wary.