Theater of Insects, an entomology book from 1658, refers to flies as “little creatures so hateful to all men.” Most people's attitude towards dipterans has not changed much since, but maybe Steven Connor's excellent new book about the role of flies in culture and myth will help transform the fly's reputation.
In Fly, Connor tells us that the fly is loathed universally because it “takes its pleasure promiscuously, restlessly, unswervably, unashamedly.” Flies trample on their food and are so single-minded when it comes to reproducing that Aristotle remarked on the difficulty of pulling copulating flies apart. This carefree lifestyle offended human sensibilities. Flies became subjects for moral allegories about the consequences of pleasure-driven lives that often end with flies singed in flames or drowned in wine. Flies seem especially irresponsible when compared with social insects: ants and bees collect food and store it for the future or to feed their young and—at least the infertile workers—never copulate.
Because of their frivolous life, flies were used to signify sin throughout history. The capacity to command flies is the mark of the devil. Satan's lieutenant Beelzebub—the lord of the flies—is portrayed in a drawing from 1863 (reproduced in Fly) as a fierce fly-like creature with the skull and crossbones symbol on its wings. Satan himself, as well as many alleged witches and even Loki, the Nordic god of mischief, all change occasionally into flies. In their fly form, they have access to houses where they steal, torment, and seduce. The situation became even worse for flies when their role in transmitting diseases was discovered in the 19th century. A ruthless campaign for their extermination was started and books like The House Fly: A Slayer of Men and The Reduction of Domestic Flies urged readers to consider killing flies a moral duty.