from ScienceNOW Daily News
March 21, 2012
The fly on the left is a puzzle. In theory, it should have evolved to look just as wasplike as the one on the right, the better to ward off hungry birds. But many members of the family Syrphidae, to which both flies belong, only vaguely resemble stinging insects.
Photographs by Steve Marshall; composite borrowed from the ScienceNOW story.