The wasp draws its ovipositor from its sheath (the black sting-like projection to the rear of its abdomen) then curls it under its body to pierce the plant tissue with great delicacy and skill. Somehow, of course, it is able to detect the presence of the larvae in which its own larvae will live, probably in this case picture-winged flies (Tephritidae).
Identifying an ichneumon such as this is difficult without catching it, and not easy even if one does. What I will try to do in this instance is to collect some of the flower heads and stalks and see if I can breed out both parasitoid and hosts.
