Parasitic Dipteran Ventral

Ventral view of a fly that emerged from one of two chrysalids of the Zebra Longwing, Heliconius charithonia.

The fly's pupal case was on the bottom of the holding container, so it emerged from the chrysalid and then pupated.

Resembles ordinary housefly, but has no elongated labium. In fact, it looks like it could bite (or at least pierce).

Any dipterists out there?