Conopids, often called thick-headed flies, are distributed worldwide except for the poles and many of the Pacific islands. Most are black and yellow, or black and white, and often strikingly resemble wasps, bees or syrphid flies. They are frequently found feeding on floral nectar.
The larvae of all conopids are internal parasites. Adult females aggressively intercept their hosts in-flight to deposit eggs. The female’s abdomen is modified to form what amounts to a “can opener” to pry open the segments of the host’s abdomen as the egg is inserted.