A really unusual medium-sized tachinid with large curved-under genitalia. In addition to that it has widely separated T1+2 marginals, a projecting mouth edge, 2 katepisternals, quite short antennae & a small ‘Sturmia-spot’.
EDIT (Monty Wood 26/9/2010): This is a male Masiphya sp. – a genus with highly distinctive male genitalia and (usually) with vibrissae high above the mouth edge. They are parasitoids of adult mantids and females often have quite barbaric piercing organs with which they attack their hosts.