What is mimicry, in short: Looking or tasting like another species to avoid being eaten by predators.
Syrphidae are amoung the most perfect mimics within Diptera and almost all, if not all are mimics of some Hymenopteran species. Most of these are black and yellow, but many show affinities with almost entirely black models.
Mimicry can be either baetsian or mulerian and the debate is still going on what category Syrphidae fall into. It is clear that many Syrphinae have slight resemblance with the black and yellow models without showing any specific morphological feature or behaviour imitating the model. In Eristalis most species have a supreficial resemblance with bees and bumblebees while many other Eristalinae are both morphologically as well as behaviourally mimicing the larger black and yellow wasps.
Below you will find some field examples of mimics and their presumed models, however it should be noted that these mimics and models have evolved side by side and it might be that the true model has become extinct or that the mimic has expanded its range and they no longer necessarely occur together.