Found some excellent pictures of the fly Tachina Grossa taken in the Netherlands, including a splendid close-up of its head. Sadly my own shots were all out of focus. The fly was found in Bruaich Jerich behind Port Charlotte.
The fly is parasitic on large, usually hairy, caterpillars - of species such as the Fox moth and the Oak eggar. The larvae feed on the caterpillar and then the adult fly emerges from the pupa.
Photo Leyton Williams-Davies; Headshot - Piet Spaans